[Tutor] running as generic file type
HiI'm very new to python, I created my first program, saved it as .py. I wanted to show it to my friends and I tested running it on another computer, one without python, and it didn't work, it gave me a list of programs to try to run it on (ex. word, IE, Mozilla). Is there any way to save it so anyone with windows can use it? Thanks for the help,Eli Zabielski ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Differnce between java and python
Another example is that Python supports Duck Typing, that is its type checking is protocol based. I see your point, but duck typing seems awfully implicit and behind-the-scenes. When you first encounter it it is. I came from a C++ and Pascal background where strict typing was the rule, Python seemed very lax. But I had the advantage of having worked in Lisp and Smalltalk too so I kind of relaxed fairly quickly. Seems like if I expect a protocol, and you provide something that claims to implement said protocol, there ought to be some contract that ensures we're dealing with the same protocol. I ought not to be able to pass my car and my nose to the same function, just because the both run(). It depends. Obviously in this example its likely that the behaviour would result in boizarre results but on the other hand if the function was race(obj1, obj2) then both car and nose could be appropriate, but in the latter case with rather horrible connotations... But seriously, Duck Typing allows for a far more expreessive and powerful use of objects. When you are no longer bound by the limitations of inheritance heirarchies you can start to build much more powerful funcions. The downside is that there is an onus on the client to sanity check the usage of the function - will it really do what I expect? Alan G Author of the learn to program web tutor http://www.freenetpages.co.uk/hp/alan.gauld ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Differnce between java and python
[Putting this back on the list so others get the context info] - Original Message - From: shivayogi kumbar [EMAIL PROTECTED] Subject: Re: [Tutor] Differnce between java and python Sir I have completed my Msc(c.s).I have worked on java and also done my project on javaa using swings ,RMI technology.The thing is now I have joined the company is working on the Python.So I would ike to know the difference between Java and Python -- In that case since you have a good knowledge of Python we can focus on a feature comparison with Java. Python has much in common with Java in that both work by compiling to byte code, however Java does so in a traditional comipile first manner whereas Python compiles at first run. Python is dynamically typed and uses protocol based polymorphism rather than inheritance based(so called Duck typing). Python is a much higher level language than Java, I'd guess the ratio of lines of code per function point is around 3:1. Python is often called 'executable pseudo code'. Python has a much more elegant syntax, it is much less based on C (Although some C-isms do show through in places) Python is more object oriented than Java which is predominantly class based. By that I mean there are lots of objects around in Python where you never see the class. Similarly there are relatively few class methods (static in Java). You can't use Java wthout without seeing at least one class statement. Python has much better support for higher order programming, functional programming and, more debateably, meta-programming. There's lots more but that should e enough for now. Check the refeences others have sent. Also check out Jython which combines the best of both worlds with remarkably few compromises. Alan G Author of the learn to program web tutor http://www.freenetpages.co.uk/hp/alan.gauld ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] running as generic file type
Eli Zabielski wrote: Hi I'm very new to python, I created my first program, saved it as .py. I wanted to show it to my friends and I tested running it on another computer, one without python, and it didn't work, it gave me a list of programs to try to run it on (ex. word, IE, Mozilla). Is there any way to save it so anyone with windows can use it? Eli, The .py file is just a text file containing the program, it requires Python to run. Just like you would not give a friend a Word file and expect them to be able to open it without the Word program on their computer, to run a Python program you need the Python interpreter. You have a few options: - Install Python on the other computer. If you have done this already on your computer you know it is not very hard. - Create an executable program that includes your program and the Python interpreter in one bundle. The program to do this is called py2exe, you can find it here: http://www.py2exe.org/ The disadvantage of this is that there is a bit to learn and the resulting executables are much larger than the original program (typically several megabytes) because they include the Python interpreter as well as your program. - Movable Python is a way of building a Python environment on a memory stick. You can bring it to another computer just by plugging in the memory stick. This might be a good solution for you especially if you already have a memory stick. http://www.voidspace.org.uk/python/movpy/ Kent ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Books
While we are on the topic of books, what book would you recommend for the experienced C++/C# programmer looking to pick up Python? I've been looking at 'Python in a Nutshell' and 'Programming Python' on amazon.co.uk, as I've found O'Reilly books good in the past. I'm mainly looking to use Python for general scripting tasks as I'm finding that batch files just aren't flexible or powerful enough on WinXP... Cheers, Daniel -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tim Johnson Sent: 22 December 2005 03:47 To: tutor@python.org Subject: Re: [Tutor] Books * Kent Johnson [EMAIL PROTECTED] [051221 13:40]: Johan Geldenhuys wrote: Are here any new books on web programming with Python? I have Python Web Programming by Steve Holden, written in 2002 covering up to python 2.0 - I believe. http://www.amazon.com/gp/product/0735710902/qid=1135222880/sr=2-1/ref=pd _bbs_b_2_1/103-3865586-6854221?s=booksv=glancen=283155 Foundations of Python Network Programming: http://www.amazon.com/gp/product/1590593715/qid=1135222941/sr=2-1/ref=pd _bbs_b_2_1/103-3865586-6854221?s=booksv=glancen=283155 -- Tim Johnson [EMAIL PROTECTED] http://www.alaska-internet-solutions.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor This email has been scanned by the MessageLabs Email Security System DISCLAIMER This message and any attachments contain privileged and confidential information intended for the use of the addressee named above. If you are not the intended recipient of this message, you are hereby notified that any use, dissemination, distribution or reproduction of this message is prohibited. Please note that we cannot guarantee that this message or any attachment is virus free or that it has not been intercepted and amended. The views of the author may not necessarily reflect those of Real Time Worlds Ltd. This email has been scanned by the MessageLabs Email Security System ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] Numeric import error
Hi all, I have installed Numeric (Suse 10.0) and it is in my site-packages folder, but I can't import the module. Any idea how to fix this/ TIA Johan ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] running as generic file type
Hi Eli, I'm very new to python, I created my first program, saved it as .py. I wanted to show it to my friends and I tested running it on another computer, one without python, and it didn't work, That's because Python is an interpreted language so it needs an interpreter to be present. This is the same as Java and most Visual Basic programs, the difference being that Microsoft provide Visual Basic and Java interpreters on Windows as standard. One of the easiest ways for you to write code that works on any machine is to use Jython. It is a vesion of Python written in Java that comes with a compiler for converting the Python code into a Java program. That will then run on any computer with Java installed. The snag is that some of the standard modules that come with Python don't work with Jython! (Thats because Java provides similar modules so you can use them instead). Most beginner programs will work in Jython but as you progress you might start hitting problems. But by then you are ready for option 2... Another way to get the programs to run is to convert the python program into a standalone executable file (a .exe) which can be done using a downloadable tool called py2exe. Py2exe just bundles a copy of the interpreter and all the modules you use into one file. Unfortunately this is not the simplest tool for a beginner to use... Also it creates quite big files - too big for a floppy disk. Of course if your friends had Apple Macs or Linux boxes then Python would be installed already. And there is a version of Python for Microsoft's new .NET framework called IronPython. But I haven't tried it and don't know how well it works. Also your friends will need to have the .NET framework installed. Finally, you could just install Python on your friends PCs too and maybe get them interested in programming :-) So there is no perfect answer (yet), sorry. But there are some options for you to try... HTH, Alan G Author of the learn to program web tutor http://www.freenetpages.co.uk/hp/alan.gauld ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] md5 message digest algorithm
hi, suprising for me is that making .py file: import md5 hash = md5.new() and running it produces : AttributeError: 'module' object has no attribute 'new' and similar : from Crypto.Hash import MD5 ImportError: cannot import name MD5 but in both cases it works on python command line intepretter. Ales -- ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Performance of Python loops vs multiple MySQL queries
On 12/21/05, Kent Johnson [EMAIL PROTECTED] wrote: Bernard Lebel wrote: Hello, Finally, after a year and a half of learning and messing around with Python, I'm writing THE code that made learn Python in the first place: a render farm client management software. I may have several questions regarding this, but for now I only have one. Congratulations Bernard, you have come a long way! [Bernard] Thanks a lot Kent, without and all the other gurus of this list, I wouldn't made it that far! The script I'm writing is the client script that runs on render nodes. It checks a database for a job to do, then based on some factors like pooling, priority, age and stuff, will determine what job it can work on. The client connects, performs evaluation of jobs, get a job, update the database, and starts the actual job. Now, there might be up to 80 clients connecting to the database at any moment to get a job to do. So understandably, I want the evaluation step to be as fast as possible. Right now, my script works this way: it selects a bunch of rows based on a few factors. Then when this is done, everything else is done in the script, that is, doesn't rely on a MySQL query. The script builds a variety of sorted lists and dictionaries, to ultimately end up with a single job. So I am wondering this: in case there are only a handful of jobs to evaluate, then I understand the script may run fast. But if it has to build lists and dictionary on thousands of jobs, then I'm affrait that it might become slower than simply running a series of queries to the database using various ordering schemes. Any advice on this? I haven't looked at your code closely so I will just offer some general advice. - Don't assume there is going to be a problem. [Bernard] Okay perhaps by problem I have not been very accurate. I meant sync problems. You see, when the script finds a job, it makes updates in the database, that is, it adds an entry into another table, and updates a certain field in the main jobs table. Other clients then testing if there is something to do rely on information that must be totally up-to-date. I just wanted to make sure I would not run into the case of multiple clients getting incorrect results because of not so up-to-date informations. Perhaps I should investigate table locks? Python dicts are very fast - they are the data structure underlying namespaces and they have been heavily optimized for years. [Bernard] Okay, good to know! - Measure! The only way to truly answer your question is to try it both ways and time it. [Bernard] You are right. My guess is that the dictionary approach will be faster. I assume the database is on a remote host since it is serving multiple clients. So at a minimum you will have the network round-trip delay for each query. - Your getJob() code seems to use some variables before they are assigned, such as tPoolIDs and aJob. Is this working code? Also it would be easier to read if you broke it up into smaller functions that each do a small piece of the problem. [Bernard] This is not working code. tPoolIDs is bound after the first query of the function, but aJob is an error of mine. Indeed I could break down the getJob() function into smaller functions. It's just that since the class is already having a fair amount of methods and this is becoming some long code, I wanted to keep everything into a single function. Also there was a consideration of performance. I have one question on the topic breaking code into small functions and performance. I have read somewhere that *any* call whatoever, that is, methods, functions and such, involve a performance cost. Is that right? In the case it is true, the performance deterioration would be proportional with the number of calls being made, so the larger the number of iterations and the more function calls, the slower the code would run, is that correct? Thanks Bernard Kent Here is a link to the current code (that build lists and dictionaries). Keep in mind it's in early alpha stage. The section to look for is the function getJob(), that starts at line 776. I have changed the extention to txt for security purposes. http://www.bernardlebel.com/scripts/nonxsi/farmclient_2.0_beta03.txt Thanks in advance Bernard ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Numeric import error
Can you open the python interpreter and write:import NumericWhat kind of error message you have?Cheers,pujoOn 12/22/05, Johan Geldenhuys [EMAIL PROTECTED] wrote:Hi all, I have installed Numeric (Suse 10.0) and it is in my site-packagesfolder, but I can't import the module.Any idea how to fix this/TIAJohan___ Tutor maillist-Tutor@python.orghttp://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Numeric import error
import Numeric Traceback (most recent call last): File "stdin", line 1, in ? ImportError: No module named Numeric Pujo Aji wrote: Can you open the python interpreter and write: import Numeric What kind of error message you have? Cheers, pujo On 12/22/05, Johan Geldenhuys [EMAIL PROTECTED] wrote: Hi all, I have installed Numeric (Suse 10.0) and it is in my site-packages folder, but I can't import the module. Any idea how to fix this/ TIA Johan ___ Tutor maillist-Tutor@python.org http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Numeric import error
Do you have other modules in your site-packages directory ?Such as spe, pyro, pyrobot etc.On 12/22/05, Johan Geldenhuys [EMAIL PROTECTED] wrote: import Numeric Traceback (most recent call last): File stdin, line 1, in ? ImportError: No module named Numeric Pujo Aji wrote: Can you open the python interpreter and write: import Numeric What kind of error message you have? Cheers, pujo On 12/22/05, Johan Geldenhuys [EMAIL PROTECTED] wrote: Hi all, I have installed Numeric (Suse 10.0) and it is in my site-packages folder, but I can't import the module. Any idea how to fix this/ TIA Johan ___ Tutor maillist-Tutor@python.org http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Numeric import error
Can you find numeric.py inside your numeric folder ?On 12/22/05, Pujo Aji [EMAIL PROTECTED] wrote: Do you have other modules in your site-packages directory ?Such as spe, pyro, pyrobot etc. On 12/22/05, Johan Geldenhuys [EMAIL PROTECTED] wrote: import Numeric Traceback (most recent call last): File stdin, line 1, in ? ImportError: No module named Numeric Pujo Aji wrote: Can you open the python interpreter and write: import Numeric What kind of error message you have? Cheers, pujo On 12/22/05, Johan Geldenhuys [EMAIL PROTECTED] wrote: Hi all, I have installed Numeric (Suse 10.0) and it is in my site-packages folder, but I can't import the module. Any idea how to fix this/ TIA Johan ___ Tutor maillist-Tutor@python.org http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Books
[EMAIL PROTECTED] said unto the world upon 2005-12-22 05:00: While we are on the topic of books, what book would you recommend for the experienced C++/C# programmer looking to pick up Python? I've been looking at 'Python in a Nutshell' and 'Programming Python' on amazon.co.uk, as I've found O'Reilly books good in the past. I'm mainly looking to use Python for general scripting tasks as I'm finding that batch files just aren't flexible or powerful enough on WinXP... Cheers, Daniel Hi Daniel, the Nutshell is the one to have at hand when coding. I don't know if one could learn from it. Dive into Python is targeted at the experienced programmer and is available both in dead tree and electronic form http://diveintopython.org/. Best, Brian vdB ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] md5 message digest algorithm
Ales Zemene wrote: hi, suprising for me is that making .py file: import md5 hash = md5.new() and running it produces : AttributeError: 'module' object has no attribute 'new' By any chance is your program called md5.py? If so it is being imported instead of the md5 library module. and similar : from Crypto.Hash import MD5 ImportError: cannot import name MD5 but in both cases it works on python command line intepretter. Are you sure you are using the same interpreter in both cases? Maybe try import sys print sys.path to make sure the directory containing Crypto.Hash is in sys.path... HTH Kent Ales ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Performance of Python loops vs multiple MySQL queries
Bernard Lebel wrote: On 12/21/05, Kent Johnson [EMAIL PROTECTED] wrote: - Don't assume there is going to be a problem. [Bernard] Okay perhaps by problem I have not been very accurate. I meant sync problems. You see, when the script finds a job, it makes updates in the database, that is, it adds an entry into another table, and updates a certain field in the main jobs table. Other clients then testing if there is something to do rely on information that must be totally up-to-date. I just wanted to make sure I would not run into the case of multiple clients getting incorrect results because of not so up-to-date informations. Perhaps I should investigate table locks? Yes, you should have a plan to avoid that kind of problem. Does your database support transactions? If so that is the easy way to ensure this - just put the whole getJob() into a transaction. - Your getJob() code seems to use some variables before they are assigned, such as tPoolIDs and aJob. Is this working code? Also it would be easier to read if you broke it up into smaller functions that each do a small piece of the problem. [Bernard] This is not working code. tPoolIDs is bound after the first query of the function, but aJob is an error of mine. Indeed I could break down the getJob() function into smaller functions. It's just that since the class is already having a fair amount of methods and this is becoming some long code, I wanted to keep everything into a single function. hmm, not a good choice. The code will be more readable and maintainable if it is broken up. If the class gets to big, think about making a helper class for some of the code. For example you might put the whole getJob() function into a class or module whose job it is to talk to the database and figure out the next job. One hallmark of a good design is that each class or module has a single responsibility. In your class you have several responsibilities that could possibly be broken out into separate modules - maintain the state of a single client - this is the job of the Client class - low-level database access - the query() function could be in a separate module - details of a single job might fit well in a Job class, this would greatly simplify Client.setJob() - getJob() might move to a utility module that just accesses the database and returns a Job object. Also there was a consideration of performance. I have one question on the topic breaking code into small functions and performance. I have read somewhere that *any* call whatoever, that is, methods, functions and such, involve a performance cost. Is that right? Yes. In the case it is true, the performance deterioration would be proportional with the number of calls being made, so the larger the number of iterations and the more function calls, the slower the code would run, is that correct? Yes, it is correct. Worrying about it at this point is gross premature optimization. It will only be a problem if you have many many function calls in a performance-critical loop. First make working code whose design clearly expresses the intent of the code. If it is too slow, then profile to find the hot spots and address them. Kent ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Performance of Python loops vs multiple MySQL queries
Thanks for all the advice Kent. Bernard On 12/22/05, Kent Johnson [EMAIL PROTECTED] wrote: Bernard Lebel wrote: On 12/21/05, Kent Johnson [EMAIL PROTECTED] wrote: - Don't assume there is going to be a problem. [Bernard] Okay perhaps by problem I have not been very accurate. I meant sync problems. You see, when the script finds a job, it makes updates in the database, that is, it adds an entry into another table, and updates a certain field in the main jobs table. Other clients then testing if there is something to do rely on information that must be totally up-to-date. I just wanted to make sure I would not run into the case of multiple clients getting incorrect results because of not so up-to-date informations. Perhaps I should investigate table locks? Yes, you should have a plan to avoid that kind of problem. Does your database support transactions? If so that is the easy way to ensure this - just put the whole getJob() into a transaction. - Your getJob() code seems to use some variables before they are assigned, such as tPoolIDs and aJob. Is this working code? Also it would be easier to read if you broke it up into smaller functions that each do a small piece of the problem. [Bernard] This is not working code. tPoolIDs is bound after the first query of the function, but aJob is an error of mine. Indeed I could break down the getJob() function into smaller functions. It's just that since the class is already having a fair amount of methods and this is becoming some long code, I wanted to keep everything into a single function. hmm, not a good choice. The code will be more readable and maintainable if it is broken up. If the class gets to big, think about making a helper class for some of the code. For example you might put the whole getJob() function into a class or module whose job it is to talk to the database and figure out the next job. One hallmark of a good design is that each class or module has a single responsibility. In your class you have several responsibilities that could possibly be broken out into separate modules - maintain the state of a single client - this is the job of the Client class - low-level database access - the query() function could be in a separate module - details of a single job might fit well in a Job class, this would greatly simplify Client.setJob() - getJob() might move to a utility module that just accesses the database and returns a Job object. Also there was a consideration of performance. I have one question on the topic breaking code into small functions and performance. I have read somewhere that *any* call whatoever, that is, methods, functions and such, involve a performance cost. Is that right? Yes. In the case it is true, the performance deterioration would be proportional with the number of calls being made, so the larger the number of iterations and the more function calls, the slower the code would run, is that correct? Yes, it is correct. Worrying about it at this point is gross premature optimization. It will only be a problem if you have many many function calls in a performance-critical loop. First make working code whose design clearly expresses the intent of the code. If it is too slow, then profile to find the hot spots and address them. Kent ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Books
While we are on the topic of books, what book would you recommend for the experienced C++/C# programmer looking to pick up Python? looking to use Python for general scripting tasks as I'm finding that batch files just aren't flexible or powerful enough on WinXP... For your particular interest I'd recommend using the official tutorial plus this list to learn the language and buy Python Programming on Win32 by Mark Hammond (O'Reilly) as a reference book. It is essential reading for the serious XP Python programmer because many of the native Python stuff is very Unix biased. Hammond shows how to avoid the pitfalls and adapt to Win32 environments. The book is a little old now (Python 1.5.2) but the vast bulk of it is still absolutely relevant, being based largely on the win32 extensions written by Hammond and found in the winall python package(or included by default in the ActiveState download). Its not all win32 specific, it includes coverage of Tkinter etc too. Still a new version would be welcome! Alan G Author of the learn to program web tutor http://www.freenetpages.co.uk/hp/alan.gauld ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Performance of Python loops vs multiple MySQL queries
Also there was a consideration of performance. I have one question on the topic breaking code into small functions and performance. I have read somewhere that *any* call whatoever, that is, methods, functions and such, involve a performance cost. Is that right? Yes it is, but its not a huge cost. Unless you have a very time critical loop calling lots of functions calling functions then don't worry unduly. And if there is a problem use the profiler to tune the bits that need tuning. The benefits of breaking code into functions in terms of readability and maintenance far outweigh the performance hit in 99% of cases. Even in the 1% its better to get it working slowly first then optimise later, exactly where needed. proportional with the number of calls being made, so the larger the number of iterations and the more function calls, the slower the code would run, is that correct? More or less, but a badly designed loop, or list comprehension will cancel out any function call overhead very quickly. And disk reads or network access will be order of magnitude slower still. Worrying about low level performance tuning before you have a problem is usually a wasted effort. High level performance tuning - getting the design clean - is another matter. In all of the cases (bar one) where I've had major performamce issues to fix they have been resolved at the architecture level (minimising network or database accesses) not at the low level code. HTH, Alan G Author of the learn to program web tutor http://www.freenetpages.co.uk/hp/alan.gauld ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Differnce between java and python (fwd)
[Keeping tutor@python.org in CC. Ok, so now we know that Shivayogi
already has Java experience.
Shivayogi might also be a little annoyed that he has to learn a new
language. We have to tread more carefully in making claims like Python
is easier than Java, because for anyone starting on another language, the
language we already know is obviously easier than the one we are trying to
learn. *grin*]
Hi Shivayogi,
There are a few nice things about Python that make common tasks easier to
do. We can go through a few examples, and if you have questions on them
or would like to see more examples, please ask and folks on the list will
be happy to talk with you. (Please make sure to keep tutor@python.org in
CC by using your email client's Reply to All feature.)
For example, Java has an iterator protocol, but until Java 1.5, it
didn't have much syntactic support. As an example, writing loops to go
across iterators involved manually next()ing the iterable and calling
hasNext():
/*** Java ***/
import java.util.*;
// ... within some method body
List words = Arrays.asList(new String[] {hello, world,
this, is,
a, test});
for (Iterator iter = words.iterator(); iter.hasNext(); ) {
String word = (String) iter.next();
System.out.println(word.toUpperCase());
}
/**/
Python's for loop, on the other hand, natively works across iterables: the
'for' loop itself is responsible for doing things like 'next()':
### Python ###
words = [hello, world, this, is, a, test]
for word in words:
print word.upper()
##
I understand that Java's for loop finally has iterator support, but from
the examples I've seen, it looks a bit syntactically heavyweight.
Another casual example where Python and Java differ is the treatment of
common types. Python doesn't have a notion of primitive types, whereas
in Java, we sometimes have to think about 'int' vs. Integer.
For example, we know that the Java method:
/**/
int double(int x) {
return x * 2;
}
/**/
breaks on large input because the declared types are primitive ints. To
make this really work, we have to use BigIntegers:
/**/
BigInteger double(BigInteger x) {
return x.multiply(new BigInteger(2));
}
/**/
On the other hand, Python integers also automatically promote themselves
to bignums rather than overflow, so the function:
##
def double(x):
return x * 2
##
just works.
Does this make sense so far? Please feel free to ask more questions.
There's also a book by Bruce Tate called Beyond Java that talks about
these issues.
Best of wishes!
-- Forwarded message --
Date: Thu, 22 Dec 2005 10:40:13 +0530
From: shivayogi kumbar [EMAIL PROTECTED]
To: Danny Yoo [EMAIL PROTECTED]
Subject: Re: [Tutor] Differnce between java and python
Sir,
I hve done my MSc(c.s).I did my project on Java.Know I have joined
the company where they work on Python.So It has forced to me learn
PYthon.SoI have approaced you
people.What are the advntages of Python over java.
Thank you
On 12/22/05, Danny Yoo [EMAIL PROTECTED] wrote:
On Wed, 21 Dec 2005, shivayogi kumbar wrote:
sir plz tell me the main differnces between java and python? And What
are the advantages of python?
Hi Shivayogi,
When you post on a mailing list that's dedicated to help teach programming
with Python, you do anticipate what kind of answers you're going to get
here, right? *grin*
Are you a beginner programmer? Do you have any previous experience with
programming? I'd really like us to turn the discussion toward what you
really want to learn. Advocacy and cheerleading is fun, of course, but
let's see if we can help you too. What are you trying to do?
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[Tutor] running a .exe
How do you run a .exe from inside a python
program.
randomexample:
print "What would you like to do today?
" print "E - email" print "I -
internet" what = input("Choose: ")
if what == "E":
Heres where i
would need torun IEXPLORE.exe
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Re: [Tutor] running a .exe
Robin Buyer wrote: How do you run a .exe from inside a python program. random example: print What would you like to do today? print E - email print I - internet what = input(Choose: ) if what == E: Heres where i would need to run IEXPLORE.exe Look at os.system() (simple) and the subprocess module (more complicated and flexible). Kent ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Books
Web/Network programming here http://www.amazon.com/gp/product/0596100329/qid=1135198935/sr=2-1/ref=pd_bbs _b_2_1/103-4720029-4050242?s=booksv=glancen=283155 Not CGI specific, and I haven't bought it yet, but I bet it's a blinder :) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Johan Geldenhuys Sent: 21 December 2005 20:59 To: David Holland Cc: tutor@python.org Subject: Re: [Tutor] Books Are here any new books on web programming with Python? Johan David Holland wrote: I would recommend python programming for the absolute beginner. ___ Yahoo! Messenger - NEW crystal clear PC to PC calling worldwide with voicemail http://uk.messenger.yahoo.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.371 / Virus Database: 267.14.3/209 - Release Date: 21/12/2005 ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] running a .exe
The internet was just an example. I'm just looking at how to open .exe from python. - Original Message - From: Liam Clarke-Hutchinson [EMAIL PROTECTED] To: 'Robin Buyer' [EMAIL PROTECTED]; tutor@python.org Sent: Thursday, December 22, 2005 7:35 PM Subject: RE: [Tutor] running a .exe Hi Robin, Normally you would use import os os.system(c:/windows/iexplore.exe) # Or wherever it lives Build as you're attempting to run internet explorer you could use - import webbrowser webbrowser.open(http://www.google.co.nz;) #Assuming IE is system default broswe Liam Clarke-Hutchinson| Contact Centre Advisor| Ministry of Economic Development DDI +64 3 962 2639 | Fax +64 3 962 6220 www.med.govt.nz -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Robin Buyer Sent: Friday, 23 December 2005 11:50 a.m. To: Tutor@python.org Subject: [Tutor] running a .exe How do you run a .exe from inside a python program. random example: print What would you like to do today? print E - email print I - internet what = input(Choose: ) if what == E: Heres where i would need to run IEXPLORE.exe A new monthly electronic newsletter covering all aspects of MED's work is now available. Subscribers can choose to receive news from any or all of seven categories, free of charge: Growth and Innovation, Strategic Directions, Energy and Resources, Business News, ICT, Consumer Issues and Tourism. See http://news.business.govt.nz for more details. http://www.govt.nz - connecting you to New Zealand central local government services Any opinions expressed in this message are not necessarily those of the Ministry of Economic Development. This message and any files transmitted with it are confidential and solely for the use of the intended recipient. If you are not the intended recipient or the person responsible for delivery to the intended recipient, be advised that you have received this message in error and that any use is strictly prohibited. Please contact the sender and delete the message and any attachment from your computer. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] running a .exe
Robin Buyer wrote:
I created a small program to test os.system:
import os.path
os.system(C:\Program Files\Internet Explorer\IEXPLORE.EXE)
when i run this from the command line I get an error message:
'C:\Program' is not recognized as an internal or external command, operable
program or batch file.
How do you put spaces into a path name?
The same way you do if you are typing the command directly to the shell - put
it in
quotes. So now there are two sets of quotes - one to tell Python it is a
string, and one
to pass to the shell:
os.system('C:\Program Files\Internet Explorer\IEXPLORE.EXE')
Alternately use subprocess.call() which takes a list of command-line parameters
so it
knows to quote the first arg:
import subprocess
subprocess.call([r'C:\Program Files\Internet Explorer\IEXPLORE.EXE'])
Also note that if you want to use paths with \ in them in Python strings you
should use a
raw string, otherwise the \ start escape sequences that you don't intend:
os.system(r'C:\Program Files\Internet Explorer\IEXPLORE.EXE')
Kent
PS please respond to the list.
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Re: [Tutor] running a .exe
Ahh. That helps a lot. Thanks.
-Robin
- Original Message -
From: Kent Johnson [EMAIL PROTECTED]
To: Python Tutor tutor@python.org
Sent: Thursday, December 22, 2005 7:46 PM
Subject: Re: [Tutor] running a .exe
Robin Buyer wrote:
I created a small program to test os.system:
import os.path
os.system(C:\Program Files\Internet Explorer\IEXPLORE.EXE)
when i run this from the command line I get an error message:
'C:\Program' is not recognized as an internal or external command,
operable
program or batch file.
How do you put spaces into a path name?
The same way you do if you are typing the command directly to the shell -
put it in
quotes. So now there are two sets of quotes - one to tell Python it is a
string, and one
to pass to the shell:
os.system('C:\Program Files\Internet Explorer\IEXPLORE.EXE')
Alternately use subprocess.call() which takes a list of command-line
parameters so it
knows to quote the first arg:
import subprocess
subprocess.call([r'C:\Program Files\Internet
Explorer\IEXPLORE.EXE'])
Also note that if you want to use paths with \ in them in Python strings
you should use a
raw string, otherwise the \ start escape sequences that you don't intend:
os.system(r'C:\Program Files\Internet Explorer\IEXPLORE.EXE')
Kent
PS please respond to the list.
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