Re: Question on for loop
On Monday, March 4, 2013 4:37:11 PM UTC, Ian wrote: On Mon, Mar 4, 2013 at 7:34 AM, Bryan Devaney bryan.deva...@gmail.com wrote: if character not in lettersGuessed: return True return False assuming a function is being used to pass each letter of the letters guessed inside a loop itself that only continues checking if true is returned, then that could work. It is however more work than is needed. If you made secretword a list,you could just set(secretword)set(lettersguessed) and check the result is equal to secretword. Check the result is equal to set(secretword), I think you mean. set(secretword).issubset(set(lettersguessed)) might be slightly more efficient, since it would not need to build and return an intersection set. One might also just do: all(letter in lettersguessed for letter in secretword) Which will be efficient if lettersguessed is already a set. You are correct. sorry for the misleading answer, was digging through old shell scripts all day yesterday and brain was obviously not not the better for it. -- http://mail.python.org/mailman/listinfo/python-list
Question on for loop
Hi all, I'm super new to python, just fyi. In the piece of code below, secretWord is a string and lettersGuessed is a list. I'm trying to find out if ALL the characters of secretWord are included in lettersGuessed, even if there are additional values in the lettersGuessed list that aren't in secretWord. What this code is doing is only checking the first character of secretWord and then returning True or False. How do I get it to iterate through ALL of the characters of secretWord? for character in secretWord: if character not in lettersGuessed: return True return False Thanks! Ro -- http://mail.python.org/mailman/listinfo/python-list
Re: Question on for loop
In fact this code is already doing what you want, but if the second character, by example, is not in secrectWord it'll jump out of the for and return. If you want that interact through the all characters and maybe count how many them are in the secrectWord, just take of the return there or do some list comprehension like: [ r for r in secrecWord if r in lettersGuessed] . []'s On Mon, Mar 4, 2013 at 9:18 AM, newtopython roshen.set...@gmail.com wrote: Hi all, I'm super new to python, just fyi. In the piece of code below, secretWord is a string and lettersGuessed is a list. I'm trying to find out if ALL the characters of secretWord are included in lettersGuessed, even if there are additional values in the lettersGuessed list that aren't in secretWord. What this code is doing is only checking the first character of secretWord and then returning True or False. How do I get it to iterate through ALL of the characters of secretWord? for character in secretWord: if character not in lettersGuessed: return True return False Thanks! Ro -- http://mail.python.org/mailman/listinfo/python-list -- Leônidas S. Barbosa (Kirotawa) Engenheiro de Software - IBM (LTC - Linux Technology Center) MsC Sistemas e Computação Bacharel em Ciências da Computação. blog nerd: corecode.wordpress.com/ http://corecode.wordpress.com/User linux : #480879 Mais sábio é aquele que sabe que não sabe (Sócrates) smile and wave - =D + o/ (Penguins of Madagascar) 日本語の学生です。 コンピュータサイエンスの学位. -- http://mail.python.org/mailman/listinfo/python-list
Re: Question on for loop
On Mon, Mar 4, 2013 at 7:18 AM, newtopython roshen.set...@gmail.com wrote: Hi all, I'm super new to python, just fyi. Welcome. Next time write a better subject line, and be sure the code you post is actually the code you are running. Provide the results you want and what you get. Provide the traceback if there is one In the piece of code below, secretWord is a string and lettersGuessed is a list. I'm trying to find out if ALL the characters of secretWord are included in lettersGuessed, even if there are additional values in the lettersGuessed list that aren't in secretWord. What this code is doing is only checking the first character of secretWord and then returning True or False. How do I get it to iterate through ALL of the characters of secretWord? for character in secretWord: if character not in lettersGuessed: I am guessing that the next two lines are actually indented in your script so I am changing them here return True return False The first time your if block is checked it will return True or False. Since you haven't shown this code in a function, as written it won't run at all. Your question makes no sense. What would it mean to look through each character and return True or False? What would make the result True? All matches, some matches? Thanks! Ro -- http://mail.python.org/mailman/listinfo/python-list -- Joel Goldstick http://joelgoldstick.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Question on for loop
On 03/04/2013 07:18 AM, newtopython wrote: Hi all, I'm super new to python, just fyi. Welcome to the Python list. In the piece of code below, secretWord is a string and lettersGuessed is a list. I'm trying to find out if ALL the characters of secretWord are included in lettersGuessed, even if there are additional values in the lettersGuessed list that aren't in secretWord. What this code is doing is only checking the first character of secretWord and then returning True or False. How do I get it to iterate through ALL of the characters of secretWord? for character in secretWord: if character not in lettersGuessed: return True return False Please post a complete sample when possible, and make sure you copy/paste it, not just retype it and hope. As written, it'll throw an exception when return is encountered. But before that, it'll complain about the indentation of the return True. Perhaps you have something like: def has_some_behavior(secretWord, lettersGuessed): for character in secretWord: if character not in lettersGuessed: return True return False If so, please copy the whole thing from your code, and explain just how you call it (what arguments are passed), what it returned, and what's wrong with that behavior. -- DaveA -- http://mail.python.org/mailman/listinfo/python-list
Re: Question on for loop
if character not in lettersGuessed: return True return False assuming a function is being used to pass each letter of the letters guessed inside a loop itself that only continues checking if true is returned, then that could work. It is however more work than is needed. If you made secretword a list,you could just set(secretword)set(lettersguessed) and check the result is equal to secretword. -- http://mail.python.org/mailman/listinfo/python-list
Re: Question on for loop
On Monday, March 4, 2013 6:18:20 AM UTC-6, newtopython wrote: [Note: Post has be logically re-arranged for your comprehensive pleasures] for character in secretWord: if character not in lettersGuessed: return True return False What this code is doing is only checking the first character of secretWord and then returning True or False. How do I get it to iterate through ALL of the characters of secretWord? Your code is a fine example of: attempting to solve too many problems at the same time. If you are having trouble understanding how to iterate over a sequence, then why would you complicate that learning experience by injecting other unsolved problems into the mix? First, solve the iteration problem. Then expand. ## START INTERACTIVE SESSION ## py s = 'multiplicity' py for char in s: ... print char m u l t i p l i c i t y ## END INTERACTIVE SESSION ## Now, we have a simple base from which to build! In the piece of code [ABOVE], secretWord is a string and lettersGuessed is a list. I'm trying to find out if ALL the characters of secretWord are included in lettersGuessed, even if there are additional values in the lettersGuessed list that aren't in secretWord. First, step away from your interpreter! Now, grab a pen and paper and write down the steps required to compare two sequences in real life. 1. Create a list of letters guessed and a string representing the secret word. secretWord = 'multiplicity' lettersGuessed = 'aeiouy' 2. For each letter in secretWord, look in lettersGuessed and see if you can find the letter, then make a note of your findings. If the letter is in IN both sequences, write [letter]=True, if not, write [letter]=False. However, this algorithm is rather naive. What happens if one or both list contain the same letter numerous times (f.e. multiplicity has 3 i chars)? Do we want the user to provide a guess for all three i chars, or will just a single guess al la price is right will do the trick? Also, do we care about the char order? Or are we merely allowing the user to guess all the letters of the word in ANY order (that seems to be your intent here!)? In any event i am not going to just gift wrap and answer for you. There are many methods of solving this problem, some are elegant, some or not elegant, some use built-in functions, some use list comprehensions, and some could just use a for loop and a single built-in function. I would highly suggest that you figure this out using the latter. Until you can achieve this, forget about list comprehension or any advanced stuff. But most importantly: Build your code in small incremental steps and solve ONE issue at a time. This is the path of a wise problem solver. -- http://mail.python.org/mailman/listinfo/python-list
Re: Question on for loop
On Mon, Mar 4, 2013 at 7:34 AM, Bryan Devaney bryan.deva...@gmail.com wrote: if character not in lettersGuessed: return True return False assuming a function is being used to pass each letter of the letters guessed inside a loop itself that only continues checking if true is returned, then that could work. It is however more work than is needed. If you made secretword a list,you could just set(secretword)set(lettersguessed) and check the result is equal to secretword. Check the result is equal to set(secretword), I think you mean. set(secretword).issubset(set(lettersguessed)) might be slightly more efficient, since it would not need to build and return an intersection set. One might also just do: all(letter in lettersguessed for letter in secretword) Which will be efficient if lettersguessed is already a set. -- http://mail.python.org/mailman/listinfo/python-list
Re: Question on for loop
El 04/03/13 09:18, newtopython escribió: Hi all, I'm super new to python, just fyi. In the piece of code below, secretWord is a string and lettersGuessed is a list. I'm trying to find out if ALL the characters of secretWord are included in lettersGuessed, even if there are additional values in the lettersGuessed list that aren't in secretWord. What this code is doing is only checking the first character of secretWord and then returning True or False. How do I get it to iterate through ALL of the characters of secretWord? for character in secretWord: if character not in lettersGuessed: return True return False Thanks! Ro Indent the return True line so that it is inside the if clause. -- http://mail.python.org/mailman/listinfo/python-list
Re: Question on for loop
On Friday, January 4, 2013 11:18:24 AM UTC+5:30, Steven D'Aprano wrote: On Thu, 03 Jan 2013 12:04:03 -0800, subhabangalore wrote: Dear Group, If I take a list like the following: fruits = ['banana', 'apple', 'mango'] for fruit in fruits: print 'Current fruit :', fruit Now, if I want variables like var1,var2,var3 be assigned to them, we may take, var1=banana, var2=apple, var3=mango but can we do something to assign the variables dynamically Easy as falling off a log. You can't write var1, var2 etc. but you can write it as var[0], var[1] etc. var = ['banana', 'apple', 'mango'] print var[0] # prints 'banana' print var[1] # prints 'apple' print var[2] # prints 'mango' Of course var is not a very good variable name. fruit or fruits would be better. -- Steven Actually in many cases it is easy if you get the variable of list value, I was trying something like, def func1(n): list1=[x1,x2,x3,x4,x5,x6,x7,x8,x9,x10] blnk=[] for i in range(len(list1)): num1=var+str(i)+=+list1[i] blnk.append(num1) print blnk Regards, Subhabrata. -- http://mail.python.org/mailman/listinfo/python-list
Re: Question on for loop
On Thu, 03 Jan 2013 12:04:03 -0800, subhabangalore wrote: Dear Group, If I take a list like the following: fruits = ['banana', 'apple', 'mango'] for fruit in fruits: print 'Current fruit :', fruit Now, if I want variables like var1,var2,var3 be assigned to them, we may take, var1=banana, var2=apple, var3=mango but can we do something to assign the variables dynamically I was thinking of var_series=['var1','var2','var3'] for var in var_series: for fruit in fruits: print var,fruits If any one can kindly suggest. Regards, Subhabrata NB: Apology for some alignment mistakes,etc. if you really want to do this ( I agree with the other replies that this is unlikely to be a good idea) then you could simply unpack the list var1,var2,var3=fruits of course if your list is of unknown length then this again becomes impractical. for most programming requirements there is a simple solution, if you find your approach is not easily implemented it is probably a good time to re- asses your approach, more of the than not you have been given a bum steer and are heading down the wrong road. See http://thedailywtf.com for an almost limitless supply of examples of programmers continuing down the wrong road ;-) -- There's nothing worse for your business than extra Santa Clauses smoking in the men's room. -- W. Bossert -- http://mail.python.org/mailman/listinfo/python-list
Question on for loop
Dear Group, If I take a list like the following: fruits = ['banana', 'apple', 'mango'] for fruit in fruits: print 'Current fruit :', fruit Now, if I want variables like var1,var2,var3 be assigned to them, we may take, var1=banana, var2=apple, var3=mango but can we do something to assign the variables dynamically I was thinking of var_series=['var1','var2','var3'] for var in var_series: for fruit in fruits: print var,fruits If any one can kindly suggest. Regards, Subhabrata NB: Apology for some alignment mistakes,etc. -- http://mail.python.org/mailman/listinfo/python-list
Re: Question on for loop
On 2013-01-03 20:04, subhabangal...@gmail.com wrote: Dear Group, If I take a list like the following: fruits = ['banana', 'apple', 'mango'] for fruit in fruits: print 'Current fruit :', fruit Now, if I want variables like var1,var2,var3 be assigned to them, we may take, var1=banana, var2=apple, var3=mango but can we do something to assign the variables dynamically I was thinking of var_series=['var1','var2','var3'] for var in var_series: for fruit in fruits: print var,fruits If any one can kindly suggest. Regards, Subhabrata NB: Apology for some alignment mistakes,etc. Why would you want to do that? Creating names dynamically like that is a bad idea. Just keep them in a list, like they are already. -- http://mail.python.org/mailman/listinfo/python-list
Re: Question on for loop
subhabangal...@gmail.com wrote:
Dear Group,
If I take a list like the following:
fruits = ['banana', 'apple', 'mango']
for fruit in fruits:
print 'Current fruit :', fruit
Now,
if I want variables like var1,var2,var3 be assigned to them, we may take,
var1=banana,
var2=apple,
var3=mango
but can we do something to assign the variables dynamically I was thinking
of
var_series=['var1','var2','var3']
for var in var_series:
for fruit in fruits:
print var,fruits
If any one can kindly suggest.
For that problem you need another data structure -- a dictionary:
lookup_fruits = {var1: banana, var2: apple, var3: mango}
var_series = [var1, var2, var3]
for var in var_series:
... print var, lookup_fruits[var]
...
var1 banana
var2 apple
var3 mango
--
http://mail.python.org/mailman/listinfo/python-list
Re: Question on for loop
Yeah, this seems like a bad idea. What exactly are you trying to do here?
Maybe using a dictionary is what you want?
d = {
'first' : 'banana',
'second' : 'apple',
'third' : 'mango'
}
for key, value in d.items():
print key, value
However I'm still not sure why you'd want to do this.
*Matt Jones*
On Thu, Jan 3, 2013 at 2:21 PM, MRAB pyt...@mrabarnett.plus.com wrote:
On 2013-01-03 20:04, subhabangal...@gmail.com wrote:
Dear Group,
If I take a list like the following:
fruits = ['banana', 'apple', 'mango']
for fruit in fruits:
print 'Current fruit :', fruit
Now,
if I want variables like var1,var2,var3 be assigned to them, we may take,
var1=banana,
var2=apple,
var3=mango
but can we do something to assign the variables dynamically I was thinking
of
var_series=['var1','var2','**var3']
for var in var_series:
for fruit in fruits:
print var,fruits
If any one can kindly suggest.
Regards,
Subhabrata
NB: Apology for some alignment mistakes,etc.
Why would you want to do that? Creating names dynamically like that is
a bad idea. Just keep them in a list, like they are already.
--
http://mail.python.org/**mailman/listinfo/python-listhttp://mail.python.org/mailman/listinfo/python-list
--
http://mail.python.org/mailman/listinfo/python-list
Re: Question on for loop
I'm interested to know why you're trying this as well. Is this something that would be helped by creating a class and then dynamically creating instances of that class? Something like... class Fruit: def __init__(self, name): self.name = name for fruit in ['banana', 'apple', 'mango']: varName = Fruit(fruit) # do stuff with varName On Thursday, January 3, 2013 2:04:03 PM UTC-6, subhaba...@gmail.com wrote: Dear Group, If I take a list like the following: fruits = ['banana', 'apple', 'mango'] for fruit in fruits: print 'Current fruit :', fruit Now, if I want variables like var1,var2,var3 be assigned to them, we may take, var1=banana, var2=apple, var3=mango but can we do something to assign the variables dynamically I was thinking of var_series=['var1','var2','var3'] for var in var_series: for fruit in fruits: print var,fruits If any one can kindly suggest. Regards, Subhabrata NB: Apology for some alignment mistakes,etc. -- http://mail.python.org/mailman/listinfo/python-list
Re: Question on for loop
On Jan 4, 6:04 am, subhabangal...@gmail.com wrote: but can we do something to assign the variables dynamically I was thinking of var_series=['var1','var2','var3'] for var in var_series: for fruit in fruits: print var,fruits Before trying to do this, write the next bit of code where you _use_ such variables. What do you do if there are no fruits? What do you do if there are 7000? You don't want variables to be optional, because otherwise you'll need to guard every usage with something like: if 'var2893' in locals(): ... Of course, you can also automate this, but why push values into a dictionary that exists for one purpose if you're not going to use it that way? If you need to deal with an unknown number of objects, use a list. If those objects have a name by which you can refer to them, use a dictionary. -- http://mail.python.org/mailman/listinfo/python-list
Re: Question on for loop
On Thu, 03 Jan 2013 12:04:03 -0800, subhabangalore wrote: Dear Group, If I take a list like the following: fruits = ['banana', 'apple', 'mango'] for fruit in fruits: print 'Current fruit :', fruit Now, if I want variables like var1,var2,var3 be assigned to them, we may take, var1=banana, var2=apple, var3=mango but can we do something to assign the variables dynamically Easy as falling off a log. You can't write var1, var2 etc. but you can write it as var[0], var[1] etc. var = ['banana', 'apple', 'mango'] print var[0] # prints 'banana' print var[1] # prints 'apple' print var[2] # prints 'mango' Of course var is not a very good variable name. fruit or fruits would be better. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Question about nested loop
Hi all, I am a very novice for Python. Currently, I am trying to read continuous columns repeatedly in the form of array. my code is like below: import numpy as np b = [] c = 4 f = open(text.file, r) while c 10: c = c + 1 for columns in ( raw.strip().split() for raw in f ): b.append(columns[c]) y = np.array(b, float) print c, y I thought that can get the arrays of the columns[5] to [10], but I only could get repetition of same arrays of columns[5]. The result was something like: 5 [1 2 3 4 .., 10 9 8] 6 [1 2 3 4 .., 10 9 8] 7 [1 2 3 4 .., 10 9 8] 8 [1 2 3 4 .., 10 9 8] 9 [1 2 3 4 .., 10 9 8] 10 [1 2 3 4 .., 10 9 8] What I can't understand is that even though c increased incrementally upto 10, y arrays stay same. Would someone help me to understand this problem more? I really appreciate any help. Thank you, Isaac -- http://mail.python.org/mailman/listinfo/python-list
Re: Question about nested loop
Isaac Won winef...@gmail.com wrote: while c 10: c = c + 1 for columns in ( raw.strip().split() for raw in f ): b.append(columns[c]) y = np.array(b, float) print c, y I thought that can get the arrays of the columns[5] to [10], but I only could get repetition of same arrays of columns[5]. I don't pretend to know list comprehension very well, but 'c' isn't incremented in the inner loop ( .. for raw in f). Hence you only append to columns[5]. Maybe you could use another 'd' indexer inside the inner-loop? But there must a more elegant way to solve your issue. (I'm a PyCommer myself). --gv -- http://mail.python.org/mailman/listinfo/python-list
Re: Question about nested loop
On 31/12/12 11:02:56, Isaac Won wrote: Hi all, I am a very novice for Python. Currently, I am trying to read continuous columns repeatedly in the form of array. my code is like below: import numpy as np b = [] c = 4 f = open(text.file, r) while c 10: c = c + 1 for columns in ( raw.strip().split() for raw in f ): b.append(columns[c]) y = np.array(b, float) print c, y I thought that can get the arrays of the columns[5] to [10], but I only could get repetition of same arrays of columns[5]. The result was something like: 5 [1 2 3 4 .., 10 9 8] 6 [1 2 3 4 .., 10 9 8] 7 [1 2 3 4 .., 10 9 8] 8 [1 2 3 4 .., 10 9 8] 9 [1 2 3 4 .., 10 9 8] 10 [1 2 3 4 .., 10 9 8] What I can't understand is that even though c increased incrementally upto 10, y arrays stay same. Would someone help me to understand this problem more? That's because the inner loop read from a file until his reaches the end of the file. Since you're not resetting the file pointer, during the second and later runs of the outer loop, the inner loop starts at the end of the file and terminates without any action. You'd get more interesting results if you rewind the file: import numpy as np b = [] c = 4 f = open(text.file, r) while c 10: c = c + 1 f.seek(0,0) for columns in ( raw.strip().split() for raw in f ): b.append(columns[c]) y = np.array(b, float) print c, y It's a bit inefficient to read the same file several times. You might consider reading it just once. For example: import numpy as np b = [] f = open(text.file, r) data = [ line.strip().split() for line in f ] f.close() for c in xrange(5, 11): for row in data: b.append(row[c]) y = np.array(b, float) print c, y Hope this helps, -- HansM -- http://mail.python.org/mailman/listinfo/python-list
Re: Question about nested loop
On Monday, December 31, 2012 5:25:16 AM UTC-6, Gisle Vanem wrote: Isaac Won winef...@gmail.com wrote: while c 10: c = c + 1 for columns in ( raw.strip().split() for raw in f ): b.append(columns[c]) y = np.array(b, float) print c, y I thought that can get the arrays of the columns[5] to [10], but I only could get repetition of same arrays of columns[5]. I don't pretend to know list comprehension very well, but 'c' isn't incremented in the inner loop ( .. for raw in f). Hence you only append to columns[5]. Maybe you could use another 'd' indexer inside the inner-loop? But there must a more elegant way to solve your issue. (I'm a PyCommer myself). --gv Thank you for your advice. I agree with you and tried to increment in inner loop, but still not very succesful. Anyway many thanks for you. -- http://mail.python.org/mailman/listinfo/python-list
Re: Question about nested loop
On Monday, December 31, 2012 6:59:34 AM UTC-6, Hans Mulder wrote: On 31/12/12 11:02:56, Isaac Won wrote: Hi all, I am a very novice for Python. Currently, I am trying to read continuous columns repeatedly in the form of array. my code is like below: import numpy as np b = [] c = 4 f = open(text.file, r) while c 10: c = c + 1 for columns in ( raw.strip().split() for raw in f ): b.append(columns[c]) y = np.array(b, float) print c, y I thought that can get the arrays of the columns[5] to [10], but I only could get repetition of same arrays of columns[5]. The result was something like: 5 [1 2 3 4 .., 10 9 8] 6 [1 2 3 4 .., 10 9 8] 7 [1 2 3 4 .., 10 9 8] 8 [1 2 3 4 .., 10 9 8] 9 [1 2 3 4 .., 10 9 8] 10 [1 2 3 4 .., 10 9 8] What I can't understand is that even though c increased incrementally upto 10, y arrays stay same. Would someone help me to understand this problem more? That's because the inner loop read from a file until his reaches the end of the file. Since you're not resetting the file pointer, during the second and later runs of the outer loop, the inner loop starts at the end of the file and terminates without any action. You'd get more interesting results if you rewind the file: import numpy as np b = [] c = 4 f = open(text.file, r) while c 10: c = c + 1 f.seek(0,0) for columns in ( raw.strip().split() for raw in f ): b.append(columns[c]) y = np.array(b, float) print c, y It's a bit inefficient to read the same file several times. You might consider reading it just once. For example: import numpy as np b = [] f = open(text.file, r) data = [ line.strip().split() for line in f ] f.close() for c in xrange(5, 11): for row in data: b.append(row[c]) y = np.array(b, float) print c, y Hope this helps, -- HansM Hi Hans, I appreciate your advice and kind tips. The both codes which you gave seem pretty interesting. Both look working for incrementing inner loop number, but the results of y are added repeatedly such as [1,2,3],[1,2,3,4,5,6], [1,2,3,4,5,6,7,8,9]. Anyhow, really thank you for your help and I will look at this problem more in detail. Isaac -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python question about for loop
jmDesktop [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] So what is n and x in the first iteration? Sorry. I'm trying. Remember how Python's range operator works. range(n, x) constructs a list that consists of all elements starting with n and up to, but /not including/, x. For example, range(3, 7) constructs the list [3, 4, 5, 6]. So what happens if you try to construct the list range(2, 2)? In this case, Python will construct an empty list -- this is its interpretation of up to, but not including n for an argument like range(n, n). This is precisely what is happening in the first iteration of the first enclosing for loop. Trace through the code; see that 2 is bound to n in the first iteration; see that the inner loop then tries to construct the list range(2, n), which is range(2, 2), which is an empty list. And a for x in [] statement will not execute even once. As it happens, your loop is perfectly correct. You are testing for divisors for a number excluding 1 and the number itself. For the number 2, the number of possible divisors satisfying this condition is an empty set. So 2 is, quite correctly, adjudged to be prime. -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python question about for loop
jmDesktop wrote: [...] So what is n and x in the first iteration? Sorry. I'm trying. Somewhat feebly, if you don't mind my saying so, but don't worry. The usual way to proceed in the face of such ignorance is to insert some form of output that will tell you the answer to your question. So: for n in range(2, 20): ... print range(2, n) ... for x in range(2, n): ... if n % x == 0: ...print n, 'equals', x, '*', n/x ...break ... else: ... print n, is prime ... [] 2 is prime [2] 3 is prime [2, 3] 4 equals 2 * 2 [2, 3, 4] 5 is prime [2, 3, 4, 5] 6 equals 2 * 3 [2, 3, 4, 5, 6] 7 is prime [2, 3, 4, 5, 6, 7] 8 equals 2 * 4 [2, 3, 4, 5, 6, 7, 8] 9 equals 3 * 3 and so on! This is the value of the interactive interpreter. regards Steve -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
basic python question about for loop
From the Python.org tutorial: for n in range(2, 10): ... for x in range(2, n): ... if n % x == 0: ... print n, 'equals', x, '*', n/x ... break ... else: ... # loop fell through without finding a factor ... print n, 'is a prime number' ... 2 is a prime number 3 is a prime number 4 equals 2 * 2 5 is a prime number 6 equals 2 * 3 7 is a prime number 8 equals 2 * 4 9 equals 3 * 3 first time 2 mod 2, 2/2, no remainder == 0, what am I doing wrong? Why did it fall through? http://www.python.org/doc/current/tut/node6.html#SECTION00630 Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python question about for loop
jmDesktop schrieb: From the Python.org tutorial: for n in range(2, 10): ... for x in range(2, n): ... if n % x == 0: ... print n, 'equals', x, '*', n/x ... break ... else: ... # loop fell through without finding a factor ... print n, 'is a prime number' ... 2 is a prime number 3 is a prime number 4 equals 2 * 2 5 is a prime number 6 equals 2 * 3 7 is a prime number 8 equals 2 * 4 9 equals 3 * 3 first time 2 mod 2, 2/2, no remainder == 0, what am I doing wrong? Why did it fall through? print out what range(2, n) for n == 2 is. And if you didn't know - 2 *IS* a prime. Diez -- http://mail.python.org/mailman/listinfo/python-list
RE: basic python question about for loop
-Original Message- From: [EMAIL PROTECTED] [mailto:python- [EMAIL PROTECTED] On Behalf Of jmDesktop Sent: Wednesday, April 09, 2008 4:51 PM To: python-list@python.org Subject: basic python question about for loop From the Python.org tutorial: for n in range(2, 10): ... for x in range(2, n): ... if n % x == 0: ... print n, 'equals', x, '*', n/x ... break ... else: ... # loop fell through without finding a factor ... print n, 'is a prime number' ... 2 is a prime number 3 is a prime number 4 equals 2 * 2 5 is a prime number 6 equals 2 * 3 7 is a prime number 8 equals 2 * 4 9 equals 3 * 3 first time 2 mod 2, 2/2, no remainder == 0, what am I doing wrong? Why did it fall through? a) 2 is prime, so nothing is wrong. b) Range isn't doing what you think it's doing: print range(2,2) [] print range(2,3) [2] print range(2,4) [2, 3] print range(2,5) [2, 3, 4] print range(1,1) [] print range(1,2) [1] print range(1,3) [1, 2] * The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential, proprietary, and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from all computers. GA622 -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python question about for loop
jmDesktop wrote: From the Python.org tutorial: for n in range(2, 10): ... for x in range(2, n): ... if n % x == 0: ... print n, 'equals', x, '*', n/x ... break ... else: ... # loop fell through without finding a factor ... print n, 'is a prime number' ... 2 is a prime number 3 is a prime number 4 equals 2 * 2 5 is a prime number 6 equals 2 * 3 7 is a prime number 8 equals 2 * 4 9 equals 3 * 3 first time 2 mod 2, 2/2, no remainder == 0, what am I doing wrong? Why did it fall through? range(2, 2) [] The loop body executes zero times. regards Steve -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python question about for loop
On Apr 9, 4:58 pm, Diez B. Roggisch [EMAIL PROTECTED] wrote: jmDesktop schrieb: From the Python.org tutorial: for n in range(2, 10): ... for x in range(2, n): ... if n % x == 0: ... print n, 'equals', x, '*', n/x ... break ... else: ... # loop fell through without finding a factor ... print n, 'is a prime number' ... 2 is a prime number 3 is a prime number 4 equals 2 * 2 5 is a prime number 6 equals 2 * 3 7 is a prime number 8 equals 2 * 4 9 equals 3 * 3 first time 2 mod 2, 2/2, no remainder == 0, what am I doing wrong? Why did it fall through? print out what range(2, n) for n == 2 is. And if you didn't know - 2 *IS* a prime. Diez- Hide quoted text - - Show quoted text - I do not understand. -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python question about for loop
On Apr 9, 4:59 pm, Reedick, Andrew [EMAIL PROTECTED] wrote: -Original Message- From: [EMAIL PROTECTED] [mailto:python- [EMAIL PROTECTED] On Behalf Of jmDesktop Sent: Wednesday, April 09, 2008 4:51 PM To: [EMAIL PROTECTED] Subject: basic python question about for loop From the Python.org tutorial: for n in range(2, 10): ... for x in range(2, n): ... if n % x == 0: ... print n, 'equals', x, '*', n/x ... break ... else: ... # loop fell through without finding a factor ... print n, 'is a prime number' ... 2 is a prime number 3 is a prime number 4 equals 2 * 2 5 is a prime number 6 equals 2 * 3 7 is a prime number 8 equals 2 * 4 9 equals 3 * 3 first time 2 mod 2, 2/2, no remainder == 0, what am I doing wrong? Why did it fall through? a) 2 is prime, so nothing is wrong. b) Range isn't doing what you think it's doing: print range(2,2) [] print range(2,3) [2] print range(2,4) [2, 3] print range(2,5) [2, 3, 4] print range(1,1) [] print range(1,2) [1] print range(1,3) [1, 2] * The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential, proprietary, and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from all computers. GA622- Hide quoted text - - Show quoted text - So what is n and x in the first iteration? Sorry. I'm trying. -- http://mail.python.org/mailman/listinfo/python-list
RE: basic python question about for loop
-Original Message- From: [EMAIL PROTECTED] [mailto:python- [EMAIL PROTECTED] On Behalf Of jmDesktop Sent: Wednesday, April 09, 2008 5:04 PM To: python-list@python.org Subject: Re: basic python question about for loop for n in range(2, 10): ... for x in range(2, n): ... if n % x == 0: ... print n, 'equals', x, '*', n/x ... break ... else: ... # loop fell through without finding a factor ... print n, 'is a prime number' ... first time 2 mod 2, 2/2, no remainder == 0, what am I doing wrong? Why did it fall through? So what is n and x in the first iteration? Sorry. I'm trying. You're never getting to n and x in the first iteration, because the 'for x in range(2, n)' loop isn't looping. This: for x in range(2, n) is equivalent in C/Perl/etc. to: for(x=2; xn; x++) which for the first iteration is: for(x=2; x2; x++) Since (2 2) is false, you never call 'if n %x == 0:' in the first iteration. Or to put it another way: Range(2, n) starts at 2, and stops _before_ n. Range(2, n) starts at 2, and stops _before_ 2. * The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential, proprietary, and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from all computers. GA622 -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python question about for loop
jmDesktop schrieb: On Apr 9, 4:58 pm, Diez B. Roggisch [EMAIL PROTECTED] wrote: jmDesktop schrieb: From the Python.org tutorial: for n in range(2, 10): ... for x in range(2, n): ... if n % x == 0: ... print n, 'equals', x, '*', n/x ... break ... else: ... # loop fell through without finding a factor ... print n, 'is a prime number' ... 2 is a prime number 3 is a prime number 4 equals 2 * 2 5 is a prime number 6 equals 2 * 3 7 is a prime number 8 equals 2 * 4 9 equals 3 * 3 first time 2 mod 2, 2/2, no remainder == 0, what am I doing wrong? Why did it fall through? print out what range(2, n) for n == 2 is. And if you didn't know - 2 *IS* a prime. Diez- Hide quoted text - - Show quoted text - I do not understand. for variable in sequence loops over a sequence. And of course it doens't if the sequence is empty, because you can't loop over something that is empty, can't you? and range(2,2) is the empty sequence. Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python question about for loop
|So what is n and x in the first iteration? Sorry. I'm trying. When n == 2, the inner loop executes 0 times (the length of range(2,n)) and then falls thru to the else clause, printing the correct answer. -- http://mail.python.org/mailman/listinfo/python-list
Question about 'for' loop
Hi, I noticed that the 'for' loop can be used inline with a list definition. For example: print [i for i in mylist] My first question is what is the name for this? I couldn't find this usage in the python docs; I only managed to learn about it through code samples on the internet. Secondly, I'm wondering how I can use this method of a for loop to append strings to strings in a list. For example: mylist = [ Hello , Hello again ] I should be able to do this: print [ i + World for i in mylist ] Which should yield the output: [Hello World, Hello again world] However, instead I get an error message saying TypeError: cannot concatenate 'str' and 'list' objects How can I achieve the above? Thanks for reading. -- http://mail.python.org/mailman/listinfo/python-list
Re: Question about 'for' loop
Robert Dailey wrote: Hi, I noticed that the 'for' loop can be used inline with a list definition. For example: print [i for i in mylist] My first question is what is the name for this? I couldn't find this usage in the python docs; I only managed to learn about it through code samples on the internet. That there is a list comprehension. Secondly, I'm wondering how I can use this method of a for loop to append strings to strings in a list. For example: mylist = [ Hello , Hello again ] I should be able to do this: print [ i + World for i in mylist ] Which should yield the output: [Hello World, Hello again world] Who says you should? Beside you, that is. I am afraid the interpreter isn't psychic, and it doesn't have a DWIM [1] mode. However, instead I get an error message saying TypeError: cannot concatenate 'str' and 'list' objects How can I achieve the above? Thanks for reading. It's just a matter of understanding the syntax in a little more depth. In a week's time it will be blindingly obvious. nicknames = [bozo, newbie, newless cloob, and welcome to c.l.py] [(hello + name) for name in nicknames] ['hello bozo', 'hello newbie', 'hello newless cloob', 'hello and welcome to c.l.py'] So, treat item [-1] from that list as the real sentiment of this message: [(hello + name) for name in nicknames][-1] 'hello and welcome to c.l.py' regards Steve [1]: Do What I Mean [and never mind what I say ...] -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC/Ltd http://www.holdenweb.com Skype: holdenweb http://del.icio.us/steve.holden --- Asciimercial -- Get on the web: Blog, lens and tag the Internet Many services currently offer free registration --- Thank You for Reading - -- http://mail.python.org/mailman/listinfo/python-list
Re: Question about 'for' loop
On Fri, 2007-08-17 at 17:45 -0500, Robert Dailey wrote: [...] Secondly, I'm wondering how I can use this method of a for loop to append strings to strings in a list. For example: mylist = [ Hello , Hello again ] I should be able to do this: print [ i + World for i in mylist ] Which should yield the output: [Hello World, Hello again world] However, instead I get an error message saying TypeError: cannot concatenate 'str' and 'list' objects How can I achieve the above? Thanks for reading. You must have done something different than what you're describing above to get that error message. The code you posted works as expected: mylist = [ ... Hello , ... Hello again ... ] print [ i + World for i in mylist ] ['Hello World', 'Hello again World'] -- Carsten Haese http://informixdb.sourceforge.net -- http://mail.python.org/mailman/listinfo/python-list
