Re: [Tutor] intefaces in python
Am 28.06.2009 um 17:00 schrieb Amit Sethi: Hi , I don't suppose python has a concept of interfaces. But can somebody tell me if their is a way i can implement something like a java interface in python. The Web Framework Zope has a notion of interfaces. http://pypi.python.org/pypi/zope.interface/3.5.1 There are some quite interesting things you can make with interfaces. Eg. the Component Architecture is build on interfaces and adapters. http://wiki.zope.org/zope3/WhatAreInterfaces More on this here: http://docs.zope.org/ juh smime.p7s Description: S/MIME cryptographic signature ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] newton's method for system of nonlinear equations
Hi can someone help me with my program demostrating Newton's method for
system of nonlinear equations below. Line 45 gives an error saying return
is outside the function and I don't know how to rectify that. I neewd this
program to print differnt values of x until the differnce between previous
x and present x is less than tol.
Please help
Thank you
from scipy import*
tol=0.01
def swapRows(v,i,j):
if len(v.getshape()) == 1: v[i],v[j] = v[j],v[i]
else:
temp = v[i].copy()
v[i] = v[j]
v[j] = temp
def swapCols(v,i,j):
temp = v[:,j].copy()
v[:,j] = v[:,i]
v[:,i] = temp
def gaussPivot(a,b,tol=1.0e-12):
n = len(b)
# Set up scale factors
s = zeros((n),float)
for i in range(n):
s[i] = max(abs(a[i,:]))
for k in range(0,n-1):
# Row interchange, if needed
p = int(argmax(abs(a[k:n,k])/s[k:n])) + k
if abs(a[p,k]) tol: error.err('Matrix is singular')
if p != k:
swap.swapRows(b,k,p)
swap.swapRows(s,k,p)
swap.swapRows(a,k,p)
# Elimination
for i in range(k+1,n):
if a[i,k] != 0.0:
lam = a[i,k]/a[k,k]
a[i,k+1:n] = a [i,k+1:n] - lam*a[k,k+1:n]
b[i] = b[i] - lam*b[k]
if abs(a[n-1,n-1]) tol: error.err('Matrix is singular')
for k in range(n-1,-1,-1):
b[k] = (b[k] - dot(a[k,k+1:n],b[k+1:n]))/a[k,k]
return b
def newtonRaphson2(f,x,tol=1.0e-9):
def jacobian(f,x):
h = 1.0e-4
n = len(x)
jac = zeros((n,n),float)
f0 = f(x)
for i in range(n):
temp = x[i]
x[i] = temp + h
f1 = f(x)
x[i] = temp
jac[:,i] = (f1 - f0)/h
return jac,f0
for i in range(30):
jac,f0 = jacobian(f,x)
if sqrt(dot(f0,f0)/len(x)) tol: return x
dx = gaussPivot(jac,-f0)
x = x + dx
if sqrt(dot(dx,dx)) tol*max(max(abs(x)),1.0): return x
print 'Too many iterations'
def f(x):
f = zeros((len(x)),float)
f[0] = sin(x[0]) + x[1]**2 + log(x[2]) - 7.0
f[1] = 3.0*x[0] + 2.0**x[1] - x[2]**3 + 1.0
f[2] = x[0] + x[1] + x[2] - 5.0
return f
x = array([1.0, 1.0, 1.0])
print newtonRaphson2(f,x)
raw_input (\nPress return to exit)
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Re: [Tutor] newton's method for system of nonlinear equations
kgotlele...@galmail.co.za wrote: Hi can someone help me with my program demostrating Newton's method for system of nonlinear equations below. Line 45 gives an error saying return is outside the function That's because you have a return outside of a function. for k in range(n-1,-1,-1): b[k] = (b[k] - dot(a[k,k+1:n],b[k+1:n]))/a[k,k] return b Where did you get this code? You haven't given us any indication of your level of python knowledge or what exactly your problem is so it's a little difficult to help you. We don't just fix programs here, we provide guidance. It's tutor not freelanceprogrammers. We'd much rather give you a fishing pole and have you fix it yourself. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] [Pythonmac-SIG] GASP on OSX 10.5.6
On 29-Jun-09, at 7:06 PM, Chris Rebert wrote: Mac OS X apparently not a supported platform: https://answers.launchpad.net/gasp-code/+faq/42 It looks like the code is pure python and depends on pycairo, so in theory it should work provided cairo which has a Quartz backend) and pycairo work (and possibly pygame). MacPorts has cairo and I imagine pycairo is easy_install'able. It's unfortunately a lot of work for a beginner... David ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] Needing Help
I am jsut beginning to learn python form a book. I have run into a problem running a script from the book. I want to ask for help. Shoudl I put the whole script into my email or put it somewhere on the web for you to look at instead. Not sure how this works, script is 68 lines. -- Bob Rea mailto:gapet...@stsams.org http://www.petard.us http://www.petard.us/blog http://www.petard.us/gallery Where is Bill Stringfellow now that we really need him? ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Needing Help
You can put your script in pastebin http://python.pastebin.com/ http://python.pastebin.com/I don't think any one will mind you pasting code in mail but pastebin makes it easier to read On Tue, Jun 30, 2009 at 10:36 PM, Bob Rea gapet...@stsams.org wrote: I am jsut beginning to learn python form a book. I have run into a problem running a script from the book. I want to ask for help. Shoudl I put the whole script into my email or put it somewhere on the web for you to look at instead. Not sure how this works, script is 68 lines. -- Bob Rea mailto:gapet...@stsams.org http://www.petard.us http://www.petard.us/blog http://www.petard.us/gallery Where is Bill Stringfellow now that we really need him? ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor -- Cheers, Vishwajeet http://www.singhvishwajeet.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Needing Help
You can use something like pastebin.com if you don't want to post huge chunks of code. You could also just tell us what problem occurred, was there a traceback (error message)? On Tue, Jun 30, 2009 at 8:06 PM, Bob Rea gapet...@stsams.org wrote: I am jsut beginning to learn python form a book. I have run into a problem running a script from the book. I want to ask for help. Shoudl I put the whole script into my email or put it somewhere on the web for you to look at instead. Not sure how this works, script is 68 lines. -- Bob Rea mailto:gapet...@stsams.org http://www.petard.us http://www.petard.us/blog http://www.petard.us/gallery Where is Bill Stringfellow now that we really need him? ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] PYTHONPATH
In working my way through the book on python, i am working in directories for chapers. Now I am on modules, and some are reused in later chapters. I have set up a directory for the modules. How do I add it to my PYTHONPATH? I can use sys.path.append but that only lasts for the session. -- Bob Rea mailto:pet...@petard.us http://www.petard.us http://www.petard.us/blog http://www.petard.us/gallery ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] PYTHONPATH-corrected
In working my way through the book on python, I am working in directories for chapers. Now I am on modules, and some are reused in later chapters. I have set up a directory for the modules. How do I add it to my PYTHONPATH? I can use sys.path.append but that only lasts for the session. This is on a suse linux 10 box -- Bob Rea mailto:pet...@petard.us http://www.petard.us http://www.petard.us/blog http://www.petard.us/gallery ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Needing Help
On Tue June 30 2009 1:17 pm, vishwajeet singh dextrou...@gmail.comwrote: You can put your script in pastebin http://python.pastebin.com/ http://python.pastebin.com/I don't think any one will mind you pasting code in mail but pastebin makes it easier to read I am making my way through _Making Use of Python_ by Rashi Gupta. I am using Python 2.4.1 I have run into problems in a script, listed at http://python.pastebin.com/m51bc3388 If I input my own name and dob, it works: b...@gandalf:~/python/MakingUse/Chapter05 python code1.py Enter your first name: Bob Enter your last name: Rea Enter your date of birth, mm-dd-: 03-05-1943 You can chose one of the following login names: 1. BobR 2. BobR53 3. RBob43 4. BRea66 If I use the data listed in the book, it fails: b...@gandalf:~/python/MakingUse/Chapter05 python code1.py Enter your first name: Laura Enter your last name: Jones Enter your date of birth, mm-dd-: 12-24-1980 You can chose one of the following login names: 1. LauraJ 2. LauraJ2412 3. JLaura80 Traceback (most recent call last): File code1.py, line 67, in ? fourth=fname[0]+lname+ age_func() TypeError: cannot concatenate 'str' and 'NoneType' objects What is going on here? Bob Rea pet...@petard.us -- Bob Rea mailto:gapet...@stsams.org http://www.petard.us http://www.petard.us/blog http://www.petard.us/gallery Where is Bill Stringfellow now that we really need him? ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] PYTHONPATH-corrected
On Tue, Jun 30, 2009 at 02:33:27PM -0400, Bob Rea wrote: In working my way through the book on python, I am working in directories for chapers. Now I am on modules, and some are reused in later chapters. I have set up a directory for the modules. How do I add it to my PYTHONPATH? I can use sys.path.append but that only lasts for the session. You set the variable in your system's environment, which is platform-dependent. For Linux, you'd typically put a line in your ~/.profile or ~/.cshrc or ~/.login or ~/.bashrc or whatever your shell uses per your account set up. So, for example, in a bash/sh shell, you'd say: export PYTHONPATH=/path/to/my/modules or for csh: setenv PYTHONPATH /path/to/my/modules Then starting the next time you log in, that will be set in your environment for you. This is on a suse linux 10 box -- Bob Rea mailto:pet...@petard.us http://www.petard.us http://www.petard.us/blog http://www.petard.us/gallery ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor -- Steve Willoughby| Using billion-dollar satellites st...@alchemy.com | to hunt for Tupperware. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Needing Help
Oops, forgot my reply-to-all On Tue, Jun 30, 2009 at 2:20 PM, Wayne sri...@gmail.com wrote: On Tue, Jun 30, 2009 at 1:06 PM, Bob Rea b...@telaugos.com wrote: snip If I input my own name and dob, it works: b...@gandalf:~/python/MakingUse/Chapter05 python code1.py Enter your first name: Bob Enter your last name: Rea Enter your date of birth, mm-dd-: 03-05-1943 You can chose one of the following login names: 1. BobR 2. BobR53 3. RBob43 4. BRea66 If I use the data listed in the book, it fails: b...@gandalf:~/python/MakingUse/Chapter05 python code1.py Enter your first name: Laura Enter your last name: Jones Enter your date of birth, mm-dd-: 12-24-1980 You can chose one of the following login names: 1. LauraJ 2. LauraJ2412 3. JLaura80 Traceback (most recent call last): File code1.py, line 67, in ? fourth=fname[0]+lname+ age_func() TypeError: cannot concatenate 'str' and 'NoneType' objects What is going on here? Well the first line after Traceback give you the line of code and the filename. Which happens to be code1.py line 67. TypeError is the type of error - specifically you tried to do something with incompatible types. In this case, adding together a string and NoneType. I'll do a little digging, but my guess is you have a problem with your age_func() not returning any value. HTH, Wayne I was correct:def age_func(): age=cur_year-year-1 if monthcur_month or (month==cur_month and daycur_day): age=age+1 return str(age) What happens if month is cur_month AND it's not my birthday? You don't return a value. But if you simply unindent the return value then it should fix it: def age_func(): age=cur_year-year-1 if monthcur_month or (month==cur_month and daycur_day): age=age+1 return str(age) Now regardless of whether age is incremented, it will return a string. HTH, Wayne -- To be considered stupid and to be told so is more painful than being called gluttonous, mendacious, violent, lascivious, lazy, cowardly: every weakness, every vice, has found its defenders, its rhetoric, its ennoblement and exaltation, but stupidity hasn’t. - Primo Levi ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Needing Help
On Tue June 30 2009 3:20 pm, you wrote: On Tue, Jun 30, 2009 at 1:06 PM, Bob Rea b...@telaugos.com wrote: snip If I input my own name and dob, it works: b...@gandalf:~/python/MakingUse/Chapter05 python code1.py Enter your first name: Bob Enter your last name: Rea Enter your date of birth, mm-dd-: 03-05-1943 You can chose one of the following login names: 1. BobR 2. BobR53 3. RBob43 4. BRea66 If I use the data listed in the book, it fails: b...@gandalf:~/python/MakingUse/Chapter05 python code1.py Enter your first name: Laura Enter your last name: Jones Enter your date of birth, mm-dd-: 12-24-1980 You can chose one of the following login names: 1. LauraJ 2. LauraJ2412 3. JLaura80 Traceback (most recent call last): File code1.py, line 67, in ? fourth=fname[0]+lname+ age_func() TypeError: cannot concatenate 'str' and 'NoneType' objects What is going on here? Well the first line after Traceback give you the line of code and the filename. Which happens to be code1.py line 67. TypeError is the type of error - specifically you tried to do something with incompatible types. In this case, adding together a string and NoneType. I'll do a little digging, but my guess is you have a problem with your age_func() not returning any value. HTH, Wayne Why doe sit work with a dob in 1943 and not with one in 1980 then, that's what really bugs me -- Bob Rea mailto:gapet...@stsams.org http://www.petard.us http://www.petard.us/blog http://www.petard.us/gallery Where is Bill Stringfellow now that we really need him? ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Needing Help
On Tue, Jun 30, 2009 at 12:27 PM, Bob Rea b...@telaugos.com wrote: Why doe sit work with a dob in 1943 and not with one in 1980 then, that's what really bugs me Nothing to do with the year. Your birth month is BEFORE June; her birth month is after. -- www.fsrtechnologies.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] Need help with python game program
. -- Message: 4 Date: Tue, 30 Jun 2009 14:27:34 -0500 From: Wayne sri...@gmail.com To: Bob Rea b...@telaugos.com Cc: tutor@python.org Subject: Re: [Tutor] Needing Help Message-ID: 333efb450906301227u76274a83x53ef42fdae41f...@mail.gmail.com Content-Type: text/plain; charset=windows-1252 Oops, forgot my reply-to-all On Tue, Jun 30, 2009 at 2:20 PM, Wayne sri...@gmail.com wrote: On Tue, Jun 30, 2009 at 1:06 PM, Bob Rea b...@telaugos.com wrote: snip If I input my own name and dob, it works: b...@gandalf:~/python/MakingUse/Chapter05 python code1.py Enter your first name: Bob Enter your last name: Rea Enter your date of birth, mm-dd-: 03-05-1943 You can chose one of the following login names: 1. BobR 2. BobR53 3. RBob43 4. BRea66 If I use the data listed in the book, it fails: b...@gandalf:~/python/MakingUse/Chapter05 python code1.py Enter your first name: Laura Enter your last name: Jones Enter your date of birth, mm-dd-: 12-24-1980 You can chose one of the following login names: 1. LauraJ 2. LauraJ2412 3. JLaura80 Traceback (most recent call last): File code1.py, line 67, in ? fourth=fname[0]+lname+ age_func() TypeError: cannot concatenate 'str' and 'NoneType' objects What is going on here? Well the first line after Traceback give you the line of code and the filename. Which happens to be code1.py line 67. TypeError is the type of error - specifically you tried to do something with incompatible types. In this case, adding together a string and NoneType. I'll do a little digging, but my guess is you have a problem with your age_func() not returning any value. HTH, Wayne I was correct:def age_func(): age=cur_year-year-1 if monthcur_month or (month==cur_month and daycur_day): age=age+1 return str(age) What happens if month is cur_month AND it's not my birthday? You don't return a value. But if you simply unindent the return value then it should fix it: def age_func(): age=cur_year-year-1 if monthcur_month or (month==cur_month and daycur_day): age=age+1 return str(age) Now regardless of whether age is incremented, it will return a string. HTH, Wayne -- To be considered stupid and to be told so is more painful than being called gluttonous, mendacious, violent, lascivious, lazy, cowardly: every weakness, every vice, has found its defenders, its rhetoric, its ennoblement and exaltation, but stupidity hasn?t. - Primo Levi -- next part -- An HTML attachment was scrubbed... URL: http://mail.python.org/pipermail/tutor/attachments/20090630/fe4ba054/attachment-0001.htm -- Message: 5 Date: Tue, 30 Jun 2009 15:27:17 -0400 From: Bob Rea b...@telaugos.com To: Wayne sri...@gmail.com Cc: tutor@python.org Subject: Re: [Tutor] Needing Help Message-ID: 200906301527.20516@telaugos.com Content-Type: text/plain; charset=utf-8 On Tue June 30 2009 3:20 pm, you wrote: On Tue, Jun 30, 2009 at 1:06 PM, Bob Rea b...@telaugos.com wrote: snip If I input my own name and dob, it works: b...@gandalf:~/python/MakingUse/Chapter05 python code1.py Enter your first name: Bob Enter your last name: Rea Enter your date of birth, mm-dd-: 03-05-1943 You can chose one of the following login names: 1. BobR 2. BobR53 3. RBob43 4. BRea66 If I use the data listed in the book, it fails: b...@gandalf:~/python/MakingUse/Chapter05 python code1.py Enter your first name: Laura Enter your last name: Jones Enter your date of birth, mm-dd-: 12-24-1980 You can chose one of the following login names: 1. LauraJ 2. LauraJ2412 3. JLaura80 Traceback (most recent call last): File code1.py, line 67, in ? fourth=fname[0]+lname+ age_func() TypeError: cannot concatenate 'str' and 'NoneType' objects What is going on here? Well the first line after Traceback give you the line of code and the filename. Which happens to be code1.py line 67. TypeError is the type of error - specifically you tried to do something with incompatible types. In this case, adding together a string and NoneType. I'll do a little digging, but my guess is you have a problem with your age_func() not returning any value. HTH, Wayne Why doe sit work with a dob in 1943 and not with one in 1980 then, that's what really bugs me -- Bob Rea mailto:gapet...@stsams.org http://www.petard.us http://www.petard.us/blog http://www.petard.us/gallery Where is Bill Stringfellow now that we really need him? -- Message: 6 Date: Tue, 30 Jun 2009 12:45:00 -0700 From: Marc Tompkins marc.tompk...@gmail.com To: Bob Rea b...@telaugos.com Cc: tutor@python.org Subject: Re: [Tutor] Needing Help Message-ID: 40af687b0906301245n3ffcc950k458e4bf629530
Re: [Tutor] Need help with python game program
jonathan wallis mindboggle...@gmail.com wrote in message news:57b8984c0906301738w1fb0e660m6bb2123399f27...@mail.gmail.com... My problem is simple, is their a way to make a variable equal multiple numbers? Such as X = 5 through 10, and then the program makes x equal something random 5 through 10, or something similar. Use the random module. There are various types of random number generation there, such as: x = random.randint(5,10) -Mark ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Need help with python game program
Please don't reply to messages like this. If you are starting a new thread, send a new e-mail to tu...@python.org. DO NOT start a thread by replying to another message. If you do, it will bork on people's machines who use threaded e-mail readers. also, please remove long, irrelevant quotations from your e-mails unless you reference it. for example, the quoted text in your e-mail is at least 10x longer than the actual content.I believe mark already answered your question. Thanks, -Luke On Tue, Jun 30, 2009 at 7:38 PM, jonathan wallis mindboggle...@gmail.comwrote: My problem is simple, is their a way to make a variable equal multiple numbers? Such as X = 5 through 10, and then the program makes x equal something random 5 through 10, or something similar. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Need help with python game program
jonathan wallis wrote:
My problem is simple, is their a way to make a variable equal multiple
numbers? Such as X = 5 through 10, and then the program makes x equal
something random 5 through 10, or something similar.
much snipping
For a short question, why did you quote an entire mailing list digest?
Answer to your question, certainly a variable can equal multiple
numbers. Several ways:
1) one at a time. X=5, then later X=7.332
2) a list of values X = [5.3, 8.001, 17, 2]
3) a dictionaryX = {tom:3, dick:42, harry:12}
4) a class. Sky's the limit here
As for random, look up the random.uniform() and random.randint() functions.
Did you have a particular programming language in mind? I've been
assuming Python, but you might be thinking something else. Have you any
experience in any other language?
DaveA
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[Tutor] Python Programming exercise
I have been going through some Python Programming exercises while following the MIT OpenCourseWare Intro to CS syllabus and am having some trouble with the first If exercise listed on this page: http://en.wikibooks.org/wiki/Python_Programming/Conditional_Statements#If_Exercises I have been able to make the module quit after entering a password three times, but can't get it to quit right away after the correct one is entered. I know this is really basic, please forgive me. I have no programming experience and have just started going through these tutorials. My code is here: http://python.pastebin.com/m6036b52e -- Daniel Sato http://www.danielsato.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] calculating a sort key and operator.attrgetter()
I have a class with an attribute which is a list rank_list this is a list
of instances f another class that has attributes quality, is_observed
if I want to sort the list by the attribute quality I can just use,
self.rank_list.sort(key=operator.attrgetter('quality'))
But I want to sort like this.
self.rank_list.sort(key=(operator.attrgetter('quality') *
operator.attrgetter('is_observed') * self.does_observe))
Will this work or is there a better way?
Thanks
Vincent Davis
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