[Tutor] append, list and variables
piotr-kam at o2.pl
Fri Jul 16 21:44:07 CEST 2010
Dnia 16-07-2010 o 19:54:01 Emile van Sebille <emile at fenx.com> napisał(a):
> On 7/16/2010 8:37 AM Mary Morris said...
>> Thanks-that helps a lot.
>> The only question I have about your pseudocode is what the 'initialize
>> result container' does. I'm pretty new to python and scripting ingeneral
>> so I'm still trying to figure everything out.
> It creates an empty data storage container for use within the processing
> loop -- if it wasn't defined before use, you'd get an error the first
> time you tried to append to it. There's some good info in the tutorial--
> see http://docs.python.org/tutorial/datastructures.html for details.
The data structure talked about is a *list* and *
['one','two'].append('e.g. a string') * is one of the list methods.
So it can be written like this:
a_result_container_aka_simply_a_list = [ ]
In general, the shorter and more descriptive a variable name is, the
You can learn more about Python's data structures and the basic concepts
of programming using the two books that I've found most useful - of course
there are many more other good books that can be used.
These books are:
1. "Learn to Program" by Alan Gauld. It's more tutorial-like in style than
the next one:
2. "How to Think Like a Computer Scientist" by Jeffrey Elkner, Allen B.
Downey and Chris Meyers.
It's more like a school textbook with exercises at the end of each chapter
and chapter 9 is called "Lists".
I've used them both to look at the same concepts from different
perspectives because Alan's book gives more information about programming
in general while the "How to Think..." is more dry, monotonous and
impersonal which can be tiring at times.
"The Python Tutorial" by Guido van Rossum is okay too (it's short and
comprehensive) but it's mainly directed to experienced programmers who can
already program in at least one language - at least that's my impression.
>> On Thu, Jul 15, 2010 at 12:58 PM, Emile van Sebille<emile at fenx.com>
>>> On 7/15/2010 11:32 AM Mary Morris said...
>>>> I'm working on a program that parses through all of our source codeat
>>>> office and i need to get my code to print a list of the decorators. I
>>>> a find(@) to locate all the decorators, but I need to assign them to a
>>>> variable somehow to get it to print a list. How do I do this? How do I
>>>> assign a variable to all the indexed strings after the @ symbol?
>>> So, decorator lines start with an '@'. Source files end in '.py'.
>>> Pseudo code could be:
>>> initialize result container
>>> with each sourcefilename in globbed list:
>>> for eachline in opened(sourcefilename):
>>> if line.startswith('@'):
>>> append [sourcefilename, line] to result
>>> # print it
>>> for eachline in result:
>>> print eachline
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