Re: [Tutor] Generator next()
On Sun, Dec 29, 2013 at 01:57:31AM -0500, Keith Winston wrote: I don't really get the inner thing, I tried to look it up, but I don't think I found the right thing, just references to nested functions. I'd like to understand what I'm looking at better, but can't figure out what question to ask... Let's start with a trivial example: a function inside another function. def f(x): print(Inside the outer function x =, x) def g(y): # a function nested inside another function print(Inside the inner function x =, x) print(Inside the inner function y =, y) return x + y return f(23) And in use, in Python 3.3: py f(1000) Inside the outer function x = 1000 Inside the inner function x = 1000 Inside the inner function y = 23 1023 The main benefit of writing the function this way is that it hides function g() from everything else. If I try to call it from outside of f(), I get an error: py g(1) Traceback (most recent call last): File stdin, line 1, in module NameError: name 'g' is not defined Note a few things: - x is a local variable to function f(). f() is free to modify x without restriction. - x is a non-local variable to the nested function g(). That means it is neither local, nor global. By default, g() cannot modify x. - y is a local variable to g(). This means that y is invisible to f(), since it doesn't exist in the outer scope. In the same way that code outside of f() cannot peer inside the function and see its local variable x, so code outside of g() cannot peer inside of it to see its local variable y. That includes f(). Now, let's crank it up a bit. In Python, functions are first-class values just like strings, numbers, lists and so forth. That means that you can return a function as the result. The usual name for this is a factory function, or just factory, a function which creates a new function and returns it. def adder_factory(n): def plus(arg): return arg + n return plus # returns the function itself If you call adder_factory(), it returns a function: py adder_factory(10) function adder_factory.locals.plus at 0xb7af6f5c What good is this? Watch carefully: py add_two = adder_factory(2) py add_three = adder_factory(3) py add_two(100) 102 py add_three(100) 103 The factory lets you programmatically create functions on the fly. add_two() is a function which adds two to whatever argument it gets. add_three() is a function which adds three to whatever argument it gets. We can create an add_whatever function without knowing in advance what whatever is going to be: py from random import randint py add_whatever = adder_factory(randint(1, 10)) py add_whatever(200) 205 py add_whatever(300) 305 So now you see the main reason for nested functions in Python: they let use create a function where you don't quite know exactly what it will do until runtime. You know the general form of what it will do, but the precise details aren't specified until runtime. There's another term you will come across from time to time: closure. The functions add_two, add_three and add_whatever above are all closures. That's a term that comes from computer science, and its exact definition isn't important, but the main thing is that in practice a closure is a function which gains at least one variable from the enclosing outer function that creates it. In the case of the various add_* functions, the inner function plus() requires a value for variable n, which it gets from enclosing adder_factory() scope. Closures are advanced but *incredibly* useful in Python. In languages like Java where functions are not first-class values, you have to do something like this instead: class Adder: def __init__(self, n): self.n = n def __call__(self, arg): return arg + self.n add_two = Adder(2) add_three = Adder(3) [more to follow] -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Generator next()
On Sun, Dec 29, 2013 at 01:57:31AM -0500, Keith Winston wrote: Also: in the timer function, it has a series of attribute assignments to 0/None after the inner function definition... from the behaviour, I assume those are applied once, the first time the timer function is called wrapping a new method/function, and then not again, but that doesn't really make sense. Again, I don't really have a well-formed question, maybe that's clear enough? Here's the code in question, stripped to the absolutely bare minimum, and with a change of name: def decorator(function): def inner(*args, **kwargs): result = function(*args, **kwargs) inner.count += 1 return result inner.count = 0 return inner Let's see what happens when you call decorator with some function as argument: def spam(n): return spam*n f = decorator(spam) What does this function f() do? Let's go through the process step by step. When we call decorator(spam), we enter the decorator() function with the local variable function set to the argument spam. The next thing that happens is that decorator() creates a new function called inner. Inside inner, stuff happens, but we don't care about that yet. (We'll come back to that in a moment.) The inner function is created, and then decorator() adds a new attribute to it: inner.count = 0 Functions, being objects, can have attributes. We can add our own. We use this attribute to keep track of how many times the function gets called. Then decorator() returns this newly created function object, complete with its attribute count=0. This new function object is assigned to the variable f. What happens when we call f()? Here's the code for f a.k.a. inner, again, stripped of the outer layer: def inner(*args, **kwargs): result = function(*args, **kwargs) inner.count += 1 return result Notice that this is a *closure* (remember them from my previous email?). There are two non-local variables inside this inner function, one called function and one called inner. function is the original spam function, the argument passed to the outer decorator function. inner is also a closure: it is the inner function itself. So inside the inner function, we have five variables: - local variable args, which collects positional arguments; - local variable kwargs, which collects keyword arguments; - non-local variable function, set to spam (the argument to the outer decorator function); - local variable result, set to the result of calling function with the collected arguments; - and finally non-local variable inner, which is set to the inner function itself. So calling f() collects all the arguments (if any) into parameters args and kwargs. Then spam gets called with those arguments, and the result saved. Then the count attribute is incremented, and finally the result returned. All this can be a bit tricky to keep track of, because the one function can be known by different names depending on where in the code you are looking. Outside of the decorator function, we have a function called spam. Inside the decorator, it is known as function. Inside the decorator, there is a nested function called inner. Outside of the decorator, it is known as f. We say that f (a.k.a. inner) is a wrapper function around spam. Alternatively, we say that f decorates spam. The special decorator syntax: @decorator def spam(n): return spam*n is a short-cut for this: def spam(n): return spam*n spam = decorator(spam) This may be a lot to digest in one sitting. Factory functions, decorators, closures, they're all fantastically useful and powerful features of Python, but they can be a bit tricky for people to wrap their brains around. [more to come] -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Generator next()
Last one! On Sun, Dec 29, 2013 at 01:57:31AM -0500, Keith Winston wrote: In the previous timer function that I was using, it defined a timer class, and then I had to instantiate it before I could use it, and then it saved a list of timing results. I think in yours, it adds attributes to each instance of a function/method, in which the relevant timings are stored. Correct. Rather than dump those attributes on the original function, it creates a new function and adds the attributes to that. The new function wraps the older one, that is, it calls the older one: def f(x): return g(x) We say that f wraps g. Now, obviously wrapping a function just to return its result unchanged is pretty pointless, normally the wrapper function will do something to the arguments, or the result, or both. Otherwise why bother? I guess that's just an observation, I've played with it a bit and it's interesting. You said you didn't like the prior implementation, I'd be interested in anything further you have to say about why: I find it too complicated for something that shouldn't be that complicated. specifically, you called it a coroutine, and a decorator factory (tell me you made that up). Any more on that? After my previous two emails, you should have an idea of what a factory is by now: it's a function that returns a new function. So a decorator factory is a function that returns a decorator. What's a decorator? In this context, it's a function that takes a function as argument and wraps it in another function. So here we have a function A which creates a function B which takes as argument a function C and returns another function D which wraps (decorates) C. That's actually not the complicated part. The complicated part is that it uses coroutines instead of normal function calls. What's a coroutine, I hear you ask? Don't ask. Actually, I can give a quick and dirty explanation of coroutines. In a normal function, you have one entry point, calling the function, and at least one exit point (a return statement, or falling off the end of the function when there's nothing more to do). We enter the function at the top, and run the code inside it until we get to the end, then we finish: def test(): do_this() # runs first do_that() # runs second do_more() # runs third # nothing more to do, the function exits In a coroutine, you don't have a single entry point, you have multiple entry points, and you use the send method to feed values into the coroutine, and get values back. This makes them very powerful. For something as simple as timing instrumentation, too powerful -- it's using a nuclear-powered bulldozer to nudge your mouse an inch to the left. -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Generator next()
On Sun, Dec 29, 2013 at 10:33:15PM +1100, Steven D'Aprano wrote: def f(x): print(Inside the outer function x =, x) def g(y): # a function nested inside another function print(Inside the inner function x =, x) print(Inside the inner function y =, y) return x + y return f(23) Oops, sorry a typo crept into this. That last line ought to be return g(23). Sorry for any confusion. -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] can't install
On Wed, Dec 25, 2013 at 2:16 AM, Tobias M. t...@tobix.eu wrote: ./configure --prefix=prefix where prefix is a custom path (e.g. in your home directory) where you want to install python. You can configure without the --prefix option, but if you just want to use this python installation for virtuelenvs I would install it separate from the rest of the system. Then you can build and install Python: Hi Tobias can i just ask. As i already have Python 3.3, when i install this separate version of 3.3, will there be a conflict on the command line when i type python3.3? This install i want just for virtualenvs but i wonder if it would replace my other 3.3 as the default on the command line? On Wednesday, December 25, 2013 1:46 PM, Lolo Lolo losermelo...@yahoo.com wrote: On Wed, Dec 25, 2013 at 2:16 AM, Tobias M. t...@tobix.eu wrote: Is this the error you get when executing distribute_setup.py? urllib.error.URLError: urlopen error unknown url type: https Thank you so much Tobias. And yes, that was the exact error message On Tue, Dec 24, 2013 at 11:36 PM, Steven D'Aprano st...@pearwood.info wrote: But the good news is that all this should become history from Python 3.4 onwards, there are plans to include pip in 3.4. also thanks Steven. I'll definately upgrade to Python 3.4___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] unicode: alpha, whitespaces and digits
Hallo, I have a unicode string s, for example uabc, uäöü, u123 or something else, and I have to find out wether 1. s is not empty and contains only digits (as in u123, but not in u3.1415) or 2. s is empty or contains only whitespaces For all other cases I would assume a normal unicode string in s, whatever that may be. For the first case it could be s.isdigit(), s.isnumeric() or s.isdecimal() - but which one is the best? For the second case it should be s.isspace(), but it works only on strings, not on unicode strings? Many thanks for any help! Ulrich -- Ulrich Goebel Paracelsusstr. 120, 53177 Bonn ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] unicode: alpha, whitespaces and digits
On 29/12/2013 13:36, Ulrich Goebel wrote: Hallo, I have a unicode string s, for example uabc, uäöü, u123 or something else, and I have to find out wether 1. s is not empty and contains only digits (as in u123, but not in u3.1415) or 2. s is empty or contains only whitespaces For all other cases I would assume a normal unicode string in s, whatever that may be. For the first case it could be s.isdigit(), s.isnumeric() or s.isdecimal() - but which one is the best? For the second case it should be s.isspace(), but it works only on strings, not on unicode strings? Many thanks for any help! Ulrich This depends on whether you are using python 2 or 3. In the latter all strings are unicode. Please see http://docs.python.org/X/library/stdtypes.html#string-methods where X is 2 or 3. You might also want to look at http://docs.python.org/3.3/howto/unicode.html -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] unicode: alpha, whitespaces and digits
On Sun, 29 Dec 2013 19:20:04 +, Mark Lawrence breamore...@yahoo.co.uk wrote: 2. s is empty or contains only whitespaces Call strip() on it. If it's now empty, it was whitespace. -- DaveA ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] can't install
Quoting Lolo Lolo losermelo...@yahoo.com: Hi Tobias can i just ask. As i already have Python 3.3, when i install this separate version of 3.3, will there be a conflict on the command line when i type python3.3? This install i want just for virtualenvs but i wonder if it would replace my other 3.3 as the default on the command line? As long as you install the new 3.3 build in a custom path (via --prefix) it will not overwrite your current installation and by default python3.3 will invoke the standard installation (probably in your /usr directory). To use your custom build in virtualenvs make sure you create the virtualenv with the python interpreter of that build (the one in the prefix/bin directory). Your virtualenv will link to this installation and when your virtualenv is active, python3.3 will invoke the interpreter from your own build. I hope this explaination is understandable (and correct), if not just ask. When using virtualenvs the first time I found it very confusing, too. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] can't install
Quoting Tobias M. t...@tobix.eu: Quoting Lolo Lolo losermelo...@yahoo.com: Hi Tobias can i just ask. As i already have Python 3.3, when i install this separate version of 3.3, will there be a conflict on the command line when i type python3.3? This install i want just for virtualenvs but i wonder if it would replace my other 3.3 as the default on the command line? As long as you install the new 3.3 build in a custom path (via --prefix) it will not overwrite your current installation and by default python3.3 will invoke the standard installation (probably in your /usr directory). To use your custom build in virtualenvs make sure you create the virtualenv with the python interpreter of that build (the one in the prefix/bin directory). Your virtualenv will link to this installation and when your virtualenv is active, python3.3 will invoke the interpreter from your own build. I hope this explaination is understandable (and correct), if not just ask. When using virtualenvs the first time I found it very confusing, too. Another hint, if you are not sure which interpreter is started when using python3.3 at the command line: In interactive mode the date and time of the build are displayed at the beginning and you can get the full path of the current python interpreter with: import sys sys.executable ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] unicode: alpha, whitespaces and digits
On Sun, Dec 29, 2013 at 02:36:32PM +0100, Ulrich Goebel wrote: Hallo, I have a unicode string s, for example uabc, uäöü, u123 or something else, and I have to find out wether 1. s is not empty and contains only digits (as in u123, but not in u3.1415) or 2. s is empty or contains only whitespaces For all other cases I would assume a normal unicode string in s, whatever that may be. For the first case it could be s.isdigit(), s.isnumeric() or s.isdecimal() - but which one is the best? Depends what you are trying to do. Only you can decide which is best. The three methods do slightly different things: - isdigit() tests for the digit characters 0...9, or their equivalent in whatever native language your computer is using. - isdecimal() tests for decimal characters. That includes the so-called Arabic numerals 0...9 (although the Arabs don't use them!) as well as other decimal digits like ٠١٢... (The above three are ARABIC-INDIC DIGIT ZERO through TWO.) - isnumeric() tests for characters which have the Unicode numeric value property. That includes decimal digits, as well as non-digit numbers such as ½ and ¾. If you want to test for something that a human reader will recognise as a whole number, s.isdigit() is probably the best one to use. For the second case it should be s.isspace(), but it works only on strings, not on unicode strings? What gives you that impression? isspace works on Unicode strings too. py ' x'.isspace() False py ''.isspace() True For the second case, you also need to check for empty strings, so you should use: not s or s.isspace() which will return True is s is empty or all whitespace, otherwise False. -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] unicode: alpha, whitespaces and digits
On Mon, Dec 30, 2013 at 09:58:10AM +1100, Steven D'Aprano wrote: What gives you that impression? isspace works on Unicode strings too. py ' x'.isspace() False py ''.isspace() True Oops, the above was copied and pasted from Python 3, which is why there are no u' prefixes. But it still holds in Python 2: py u''.isspace() True py u' x'.isspace() False Sorry for any confusion. -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] unicode: alpha, whitespaces and digits
On Sun, Dec 29, 2013 at 5:58 PM, Steven D'Aprano st...@pearwood.info wrote:
If you want to test for something that a human reader will recognise as
a whole number, s.isdigit() is probably the best one to use.
isdigit() includes decimal digits plus other characters that have a digit value:
print u'\N{superscript two}'
²
unicodedata.digit(u'\N{superscript two}')
2
However, int(u'\N{superscript two}') raises a ValueError. int() only
accepts the subset of digits that are isdecimal().
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[Tutor] Using Regular Expression to extracting string in brackets on a list
Hello, I am trying to rewrite some contents on a long list that contains words within brackets and outside brackets and I'm having trouble extracting the words within brackets, especially since I have to add the append function for list as well. Does anyone have any suggestions? Thank you! *An example of list*: ['hypothetical protein BRAFLDRAFT_208408 [Branchiostoma floridae]\n', 'hypoxia-inducible factor 1-alpha [Mus musculus]\n', 'hypoxia-inducible factor 1-alpha [Gallus gallus]\n' ] *What I'm trying to extract out of this*: ['Branchiostoma floridae', 'Mus musculus', 'Gallus gallus'] ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Using Regular Expression to extracting string in brackets on a list
On Sun, Dec 29, 2013 at 4:02 PM, Jing Ai jai...@g.rwu.edu wrote: Hello, I am trying to rewrite some contents on a long list that contains words within brackets and outside brackets and I'm having trouble extracting the words within brackets, especially since I have to add the append function for list as well. Does anyone have any suggestions? Thank you! *An example of list*: ['hypothetical protein BRAFLDRAFT_208408 [Branchiostoma floridae]\n', 'hypoxia-inducible factor 1-alpha [Mus musculus]\n', 'hypoxia-inducible factor 1-alpha [Gallus gallus]\n' ] Is the above line a python list, or is it what you get when you read a line of a data file. The reason I ask, is if it is a list you can split the list by looping of each list item. Then just maybe try some of these ideas: http://stackoverflow.com/questions/10017147/python-replace-characters-in-string *What I'm trying to extract out of this*: ['Branchiostoma floridae', 'Mus musculus', 'Gallus gallus'] ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor -- Joel Goldstick http://joelgoldstick.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Using Regular Expression to extracting string in brackets on a list
On Sun, Dec 29, 2013 at 04:02:01PM -0500, Jing Ai wrote:
Hello,
I am trying to rewrite some contents on a long list that contains words
within brackets and outside brackets and I'm having trouble extracting the
words within brackets, especially since I have to add the append function
for list as well. Does anyone have any suggestions? Thank you!
*An example of list*:
['hypothetical protein BRAFLDRAFT_208408 [Branchiostoma floridae]\n',
'hypoxia-inducible factor 1-alpha [Mus musculus]\n', 'hypoxia-inducible
factor 1-alpha [Gallus gallus]\n' ]
*What I'm trying to extract out of this*:
['Branchiostoma floridae', 'Mus musculus', 'Gallus gallus']
You have a list of strings. Each string has exactly one pair of square
brackets []. You want the content of the square brackets.
Start with a function that extracts the content of the square brackets
from a single string.
def extract(s):
start = s.find('[')
if start == -1:
# No opening bracket found. Should this be an error?
return ''
start += 1 # skip the bracket, move to the next character
end = s.find(']', start)
if end == -1:
# No closing bracket found after the opening bracket.
# Should this be an error instead?
return s[start:]
else:
return s[start:end]
Let's test it and see if it works:
py s = 'hypothetical protein BRAFLDRAFT_208408 [Branchiostoma floridae]\n'
py extract(s)
'Branchiostoma floridae'
So far so good. Now let's write a loop:
names = []
for line in list_of_strings:
names.append(extract(line))
where list_of_strings is your big list like the example above.
We can simplify the loop by using a list comprehension:
names = [extract(line) for line in list_of_strings]
If you prefer to use a regular expression, that's simple enough. Here's
a new version of the extract function:
import re
def extract(s):
mo = re.search(r'\[(.*)\]', s)
if mo:
return mo.group(1)
return ''
The list comprehension remains the same.
--
Steven
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Re: [Tutor] Using Regular Expression to extracting string in brackets on a list
On Sun, Dec 29, 2013 at 9:00 PM, Jing Ai jai...@g.rwu.edu wrote: Thanks, but I don't think I can get out the string in the brackets by only replacing other items...(there's too many things to replace and may interfere with the items within the string). I am not sure what you mean by your previous sentence. Check out Steven's excellent answer. Also, remember to reply to the list, or no one will see your question. Good luck On Sun, Dec 29, 2013 at 7:08 PM, Joel Goldstick joel.goldst...@gmail.comwrote: On Sun, Dec 29, 2013 at 4:02 PM, Jing Ai jai...@g.rwu.edu wrote: Hello, I am trying to rewrite some contents on a long list that contains words within brackets and outside brackets and I'm having trouble extracting the words within brackets, especially since I have to add the append function for list as well. Does anyone have any suggestions? Thank you! *An example of list*: ['hypothetical protein BRAFLDRAFT_208408 [Branchiostoma floridae]\n', 'hypoxia-inducible factor 1-alpha [Mus musculus]\n', 'hypoxia-inducible factor 1-alpha [Gallus gallus]\n' ] Is the above line a python list, or is it what you get when you read a line of a data file. The reason I ask, is if it is a list you can split the list by looping of each list item. Then just maybe try some of these ideas: http://stackoverflow.com/questions/10017147/python-replace-characters-in-string *What I'm trying to extract out of this*: ['Branchiostoma floridae', 'Mus musculus', 'Gallus gallus'] ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor -- Joel Goldstick http://joelgoldstick.com -- Joel Goldstick http://joelgoldstick.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Generator next()
Wow Steven, this is great.I'll be brief I'm on a phone def f(x): print(Inside the outer function x =, x) def g(y): # a function nested inside another function print(Inside the inner function x =, x) print(Inside the inner function y =, y) return x + y return f(23) Actually as I was forming my question I sorted out what's going on. Your examples and descriptions are very clear and exceedingly helpful, you could write a useful book. Thanks for all the help. Now on to your next two posts ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Generator next()
This is all really quite awesome, though I'm sure it'll be a while before these are really available tools for me. I think I get(a bit more than) the basic concept. Thanks! is a short-cut for this: def spam(n): return spam*n spam = decorator(spam) This may be a lot to digest in one sitting. Factory functions, decorators, closures, they're all fantastically useful and powerful features of Python, but they can be a bit tricky for people to wrap their brains around. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Generator next()
Hah,I must understand,I read it that way! Oops, sorry a typo crept into this. That last line ought to be return g(23). Sorry for any confusion. -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Using Regular Expression to extracting string in brackets on a list
Thank you all for the suggestions! I decided to use Steven's re loop in the end. Joel, what i meant earlier was that the link you sent seems to suggest me to replace some characters in the list and I'm not sure how it would work... On Sun, Dec 29, 2013 at 9:24 PM, Joel Goldstick joel.goldst...@gmail.comwrote: On Sun, Dec 29, 2013 at 9:00 PM, Jing Ai jai...@g.rwu.edu wrote: Thanks, but I don't think I can get out the string in the brackets by only replacing other items...(there's too many things to replace and may interfere with the items within the string). I am not sure what you mean by your previous sentence. Check out Steven's excellent answer. Also, remember to reply to the list, or no one will see your question. Good luck On Sun, Dec 29, 2013 at 7:08 PM, Joel Goldstick joel.goldst...@gmail.com wrote: On Sun, Dec 29, 2013 at 4:02 PM, Jing Ai jai...@g.rwu.edu wrote: Hello, I am trying to rewrite some contents on a long list that contains words within brackets and outside brackets and I'm having trouble extracting the words within brackets, especially since I have to add the append function for list as well. Does anyone have any suggestions? Thank you! *An example of list*: ['hypothetical protein BRAFLDRAFT_208408 [Branchiostoma floridae]\n', 'hypoxia-inducible factor 1-alpha [Mus musculus]\n', 'hypoxia-inducible factor 1-alpha [Gallus gallus]\n' ] Is the above line a python list, or is it what you get when you read a line of a data file. The reason I ask, is if it is a list you can split the list by looping of each list item. Then just maybe try some of these ideas: http://stackoverflow.com/questions/10017147/python-replace-characters-in-string *What I'm trying to extract out of this*: ['Branchiostoma floridae', 'Mus musculus', 'Gallus gallus'] ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor -- Joel Goldstick http://joelgoldstick.com -- Joel Goldstick http://joelgoldstick.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Using Regular Expression to extracting string in brackets on a list
Steven's answer is probably a lot more robust, but I would use a simple split. mylist = ['hypothetical protein BRAFLDRAFT_208408 [Branchiostoma floridae]\n', 'hypoxia-inducible factor 1-alpha [Mus musculus]\n', 'hypoxia-inducible factor 1-alpha [Gallus gallus]\n' ] for item in mylist: item.split([)[1].split(])[0] -- Bodsda On 30 December 2013 03:28, Jing Ai jai...@g.rwu.edu wrote: Thank you all for the suggestions! I decided to use Steven's re loop in the end. Joel, what i meant earlier was that the link you sent seems to suggest me to replace some characters in the list and I'm not sure how it would work... On Sun, Dec 29, 2013 at 9:24 PM, Joel Goldstick joel.goldst...@gmail.comwrote: On Sun, Dec 29, 2013 at 9:00 PM, Jing Ai jai...@g.rwu.edu wrote: Thanks, but I don't think I can get out the string in the brackets by only replacing other items...(there's too many things to replace and may interfere with the items within the string). I am not sure what you mean by your previous sentence. Check out Steven's excellent answer. Also, remember to reply to the list, or no one will see your question. Good luck On Sun, Dec 29, 2013 at 7:08 PM, Joel Goldstick joel.goldst...@gmail.com wrote: On Sun, Dec 29, 2013 at 4:02 PM, Jing Ai jai...@g.rwu.edu wrote: Hello, I am trying to rewrite some contents on a long list that contains words within brackets and outside brackets and I'm having trouble extracting the words within brackets, especially since I have to add the append function for list as well. Does anyone have any suggestions? Thank you! *An example of list*: ['hypothetical protein BRAFLDRAFT_208408 [Branchiostoma floridae]\n', 'hypoxia-inducible factor 1-alpha [Mus musculus]\n', 'hypoxia-inducible factor 1-alpha [Gallus gallus]\n' ] Is the above line a python list, or is it what you get when you read a line of a data file. The reason I ask, is if it is a list you can split the list by looping of each list item. Then just maybe try some of these ideas: http://stackoverflow.com/questions/10017147/python-replace-characters-in-string *What I'm trying to extract out of this*: ['Branchiostoma floridae', 'Mus musculus', 'Gallus gallus'] ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor -- Joel Goldstick http://joelgoldstick.com -- Joel Goldstick http://joelgoldstick.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
