Re: [Tutor] Tutor Digest, Vol 100, Issue 58
On 26/06/12 02:22, Steven D'Aprano wrote: I think you've messed up your quoting. It was Mike Nickey, not Emile, who suggested using w[0] == 'x'. Yes, but Emile's comment was in context of Mike's assertion about w[0]. However, reading it back I think that the This in Emile's comment was actually intended to refer back to the startswith discussed in his earlier(unquoted) comment... -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] Looping over histogram plots
Hello all,
I have been making some big multiplots lately and found a nice little
way of writing out 30 plots as follows, this part works great and leads up
to my question, here I have 30 sets defined by the set=(), in this case I
get a nice arrangement of 30 plots for V(GSR) and Log(g) (2 variables):
-
fig, axes = plt.subplots(nrows=5, ncols=6, figsize=(12,6))
index=0
for b in axes:
for ax in b:
index=index+1
set=(dat['a'+str(index)] == 1.00)
#write the data
ax.plot(VGSR[set],logg[set],'.b')
#label the axis
if index==13.0:
ax.set_ylabel('counts')
if index = 25.0:
ax.set_xlabel('VGSR')
plt.show()
However, if I want a histogram plot instead, I get my histogram only on the
last i.e. set(dat['a30']==1) plot, so instead of 30 nice plots I get 29
empty ones and one crowded plot with some number of histograms in it. The
set is the same, the data is the same, the only difference is the
histogram, the code also looks pretty much the same, it is:
#--
fig, axes = plt.subplots(nrows=5, ncols=6, figsize=(12,6))
index=0
for b in axes:
for ax in b:
index=index+1
set=(dat['a'+str(index)] == 1.00)
#write the data
P.hist(VGSR[set],bins=30, normed=True)
#label the axis
if index==13.0:
ax.set_ylabel('counts')
if index = 25.0:
ax.set_xlabel('VGSR')
plt.show()
#---
Here I use import pylab as P and import matplotlib.pyplot as plt
Any ideas would be appreciated, thanks in advance!
~Elaina
--
PhD Candidate
Department of Physics and Astronomy
Faculty of Science
Macquarie University
North Ryde, NSW 2109, Australia
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Re: [Tutor] Looping over histogram plots
Message: 1 Date: Tue, 26 Jun 2012 18:40:50 +1000 From: Elaina Ann Hyde elainah...@gmail.com To: tutor@python.org Subject: [Tutor] Looping over histogram plots snip set=(dat['a'+str(index)] == 1.00) You should not override the builtin set() type [1] as you've done here by assigning it. #write the data P.hist(VGSR[set],bins=30, normed=True) I am not familiar with matplotlib, etc. but given that the primary difference in your two code samples is where you write the data, I suspect you want something like: ax.plot(P.hist(VGSR[set],bins=30, normed=True)) Take care, Don [1] http://docs.python.org/library/stdtypes.html#set ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] Barcode decoder in Python
Hi everyone, Is there any decent barcode decoder software which one could use to read image barcodes and return a result to a calling function/ app? I wish to implement a Python server backend which would import and use such a module (if it were that, for instance). Thanks. -- Regards, Sithembewena Lloyd Dube ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] Generating random alphanumeric codes
HI, Would anyone have tips on how to generate random 4-digit alphanumeric codes in python? Also, how does one calculate the number of possible combinations? Thanks in advance. -- Regards, Sithembewena Lloyd Dube ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Generating random alphanumeric codes
On Tue, Jun 26, 2012 at 4:52 PM, Sithembewena Lloyd Dube zebr...@gmail.comwrote: HI, Would anyone have tips on how to generate random 4-digit alphanumeric codes in python? Also, how does one calculate the number of possible combinations? Thanks in advance. Python's, random module is your friend. I'd suggest looking at the random.choice() function. As for the number of possibilities, if your codes are not case sensitive, you'll have 10 + 26 = 36 possibilities for each character/digit. 4 digits, so 36**4 possible codes. Hugo ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Generating random alphanumeric codes
First of all, determine your alphabet (the pool of characters you'll derive your 4-character code from): - For example, using an English alphabet with both lowercase and uppercase letters and digits 0-9 makes for 62 characters (26 + 26 + 10). Then, ask if you want to allow a character to repeat itself in the 4-character code. - If so, then it's easy: take the length of your alphabet, and calculate (length)^4. In my example above, it would be 62^4 = 14,776,336 - If not, then it's a little more complicated, calculate (length) * (length-1) * (length-2) * (length-3), or in other words the factorial of length minus the factorial of (length - 4). In my example, 62! - (62-4)! = 13,388,280 AR On Tue, Jun 26, 2012 at 10:52 AM, Sithembewena Lloyd Dube zebr...@gmail.com wrote: HI, Would anyone have tips on how to generate random 4-digit alphanumeric codes in python? Also, how does one calculate the number of possible combinations? Thanks in advance. -- Regards, Sithembewena Lloyd Dube ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Generating random alphanumeric codes
Correcting what was said below. - If not, then it's a little more complicated, calculate (length) * (length-1) * (length-2) * (length-3), or in other words the factorial of length divided by the factorial of (length - 4). In my example, 62! / (62-4)! = 13,388,280 On Tue, Jun 26, 2012 at 11:08 AM, taserian taser...@gmail.com wrote: First of all, determine your alphabet (the pool of characters you'll derive your 4-character code from): - For example, using an English alphabet with both lowercase and uppercase letters and digits 0-9 makes for 62 characters (26 + 26 + 10). Then, ask if you want to allow a character to repeat itself in the 4-character code. - If so, then it's easy: take the length of your alphabet, and calculate (length)^4. In my example above, it would be 62^4 = 14,776,336 - If not, then it's a little more complicated, calculate (length) * (length-1) * (length-2) * (length-3), or in other words the factorial of length minus the factorial of (length - 4). In my example, 62! - (62-4)! = 13,388,280 AR On Tue, Jun 26, 2012 at 10:52 AM, Sithembewena Lloyd Dube zebr...@gmail.com wrote: HI, Would anyone have tips on how to generate random 4-digit alphanumeric codes in python? Also, how does one calculate the number of possible combinations? Thanks in advance. -- Regards, Sithembewena Lloyd Dube ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Tutor Digest, Vol 100, Issue 58
On 6/26/2012 1:10 AM Alan Gauld said... On 26/06/12 02:22, Steven D'Aprano wrote: I think you've messed up your quoting. It was Mike Nickey, not Emile, who suggested using w[0] == 'x'. Yes, but Emile's comment was in context of Mike's assertion about w[0]. However, reading it back I think that the This in Emile's comment was actually intended to refer back to the startswith discussed in his earlier(unquoted) comment... Actually, my first comment at that location was phrased with a negative as in something like 'and doesn't suffer the side effect of failing when the string is empty like this does' but as I edited before hitting send I rephrased my response and left the 'this' oinappropriately placed. Emile ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Generating random alphanumeric codes
Hello, : Would anyone have tips on how to generate random 4-digit : alphanumeric codes in python? Also, how does one calculate the : number of possible combinations? Here are some thoughts that come to my mind: import string import random # -- technique #1, using random.choice print ''.join([random.choice(string.lowercase) for x in range(4)]) # -- technique #2, using random.shuffle t = [ x for x in string.lowercase ] random.shuffle(t) ''.join(t[0:4]) # -- technique #3, using random.sample ''.join(random.sample(string.lowercase,4)) I would be quite surprised if there were not more efficient ways of accomplishing this. -Martin -- Martin A. Brown http://linux-ip.net/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Generating random alphanumeric codes
On 06/26/2012 03:47 PM, Martin A. Brown wrote: Hello, : Would anyone have tips on how to generate random 4-digit : alphanumeric codes in python? Also, how does one calculate the : number of possible combinations? Here are some thoughts that come to my mind: import string import random # -- technique #1, using random.choice print ''.join([random.choice(string.lowercase) for x in range(4)]) # -- technique #2, using random.shuffle t = [ x for x in string.lowercase ] random.shuffle(t) ''.join(t[0:4]) # -- technique #3, using random.sample ''.join(random.sample(string.lowercase,4)) I would be quite surprised if there were not more efficient ways of accomplishing this. -Martin Two problems that I see: string.lowercase includes the lowercase letters, but not the digits. Your methods 2 and 3 produce different results than method1. The OP never specified which he wanted, but the distinction can well be important. Likewise his query about how many possibilities there are depends on the same question: Are duplicates permitted between the four characters in any given answer. -- DaveA ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] Re.findall question
I'm a bit confused about extracting data using re.search or re.findall. Say I have the following code: tuples = re.findall(r'blahblah(\d+)yattayattayatta(\w+)moreblahblahblah(\w+)over', text) So I'm looking for that string in 'text', and I intend to extract the parts which have parentheses around them. And it works: the variable tuples, which I assigned to get the return of re.findall, returns a tuple list, each 'element' therein being a tuple of 3 elements (which is what I wanted since I had 3 sets of parentheses). My question is how does Python know to return just the part in the parentheses and not to return the blahblah and the yattayattayatta, etc...? The 're.search' function returns the whole thing, and if I want just the parentheses parts, I do tuples.group(1) or tuples.group(2) or tuples.group(3), depending on which set of parentheses I want. Does the re.findall command by default ignore anything outside of the parentheses and only return the parentheses as a grouping withing one tuple (i.e., the first element in tuples would be, as it is, a list comprised of 3 elements corresponding respectively to the 1st, 2nd, and 3rd parentheses)? Thank you for reading. -Alex ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Re.findall question
On 26/06/12 23:30, Alexander Quest wrote: My question is how does Python know to return just the part in the parentheses and not to return the blahblah and the yattayattayatta, etc...? If you want to know *how* Python does it you will have to read the module code (probably in C so download the source code) ... Does the re.findall command by default ignore anything outside of the parentheses and only return the parentheses as a grouping withing one tuple The help() function returns: -- findall(pattern, string, flags=0) Return a list of all non-overlapping matches in the string. If one or more groups are present in the pattern, return a list of groups; this will be a list of tuples if the pattern has more than one group. Empty matches are included in the result. -- So that's what its defined to do. How it does it is another matter. -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looping over histogram plots
Dear Don, Thanks for the comment, the set type is no problem for me, this is just a variable that I call set... and it works great for my purposes, I do suspect it is something in the way that matplotlib/pyplot deals with histograms, but I have not so far been able to find the right syntax. Note, the first code example works great, it is only the second (with the hist attempt) that does not do well. It creates 29 blank plots and 1 histogram instead of 30 histograms... so probably it does need a different phrasing, but the one you suggest gives invalid syntax. ~Elaina On Tue, Jun 26, 2012 at 9:19 PM, Don Jennings dfjenni...@gmail.com wrote: Message: 1 Date: Tue, 26 Jun 2012 18:40:50 +1000 From: Elaina Ann Hyde elainah...@gmail.com To: tutor@python.org Subject: [Tutor] Looping over histogram plots snip set=(dat['a'+str(index)] == 1.00) You should not override the builtin set() type [1] as you've done here by assigning it. #write the data P.hist(VGSR[set],bins=30, normed=True) I am not familiar with matplotlib, etc. but given that the primary difference in your two code samples is where you write the data, I suspect you want something like: ax.plot(P.hist(VGSR[set],bins=30, normed=True)) Take care, Don [1] http://docs.python.org/library/stdtypes.html#set -- PhD Candidate Department of Physics and Astronomy Faculty of Science Macquarie University North Ryde, NSW 2109, Australia ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looping over histogram plots
Yay Python:
The solution was a syntax one, if anyone else ever feels like massively
multi-plotting histograms, here is the working code:
#--
fig, axes = plt.subplots(nrows=5, ncols=6, figsize=(12,6))
index=0
for b in axes:
for ax in b:
index=index+1
set=(dat['a'+str(index)] == 1.00)
#write the data
n, bins, patches = ax.hist(VGSR[set], 30, normed=1)
#label the axis
if index==13.0:
ax.set_ylabel('counts')
if index = 25.0:
ax.set_xlabel('VGSR')
plt.show()
#---
~Elaina Hyde
--
PhD Candidate
Department of Physics and Astronomy
Faculty of Science
Macquarie University
North Ryde, NSW 2109, Australia
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