easy questions from python newbie

[James Stroud]

John Machin wrote:
> James Stroud wrote:
> 
>>walterbyrd wrote:
>>
>>>This is the first real python program I have ever worked on. What I
>>>want to do is:
>>>1) count identical records in a cvs file
>>>2) create a new file with quantities instead duplicate records
>>>3) open the new file in ms-excel
>>>
>>>For example, I will start with a file like:
>>>
>>>1001
>>>1012
>>>1008
>>>1012
>>>1001
>>>1001
>>>
>>>and finish with a file like:
>>>
>>>1001,3
>>>1008,1
>>>1012,2
>>>
>>>What I need to know:
>>>1) is there a function in python that will sort a file into another
>>>file. Something like:
>>>sort file1.txt > file2.txt from the DOS command line. I know there is
>>>also a similar "sort" funtion in Unix.
>>
>>import os
>>os.system('sort file1.txt > file2.txt')
>>
>>
>>>2) is there a function in python that will correctly load a csv file
>>>into an excel spreadsheet,
>>>and open that spreadsheet.
>>
>>What's with the excel files? You must be in industry. Excel opens csv
>>files, no problem. In Mac OS X, you can do this:
>>
>>   os.system('open -a /Applications/Excel %s' % 'my_file.csv')
>>
>>It probably requires a nauseating journey through a bunch of hoops to do
>>the equivalent in window$. But you haven't specified your operating
>>system, so I optimistically assume a best-case (OS X) and not a
>>worst-case (window$). If worst-case, I'm truly sorry for your misfortune.
> 
> 
> Hey d00d, what's with the attit00d? All those $ signs? Do you get Excel
> for free on Mac OS X or does your department pay for it?  Us 'doze
> dummies w/o a big endowment like UCLA wouldn't/couldn't afford that.
> Out here in the boonies we have to download the free stuff.


I use FC4 and open office. I had to fire up a window$ machine to test 
the CSV thing, d00d.

> C:\junk>python
> Python 2.4.3 (#69, Mar 29 2006, 17:35:34) [MSC v.1310 32 bit (Intel)]
> on win32
> Type "help", "copyright", "credits" or "license" for more information.
> 
>>>>import os
>>>>os.system('"C:\Program Files\OpenOffice.org 2.0\program\scalc" foo.csv')
> 
> 0
> 
> 
> Look, d00d, no hoops.

Glad for you.

>>>3) I will probably be working with 50 items, or less, would it be best
>>>for me to do this with a
>>>multi-diminsional array? For example: sort the file, read a rec into
>>>the array, if the next rec is the same then incr the count, otherwise
>>>add a new rec with a count of 1. Then write the array to a file?
>>>
>>
>>Ah, a real question. Use a dict:
>>
>>if adict.has_key(some_key):
> 
> 
> Hey, d00d, ask the department sysadmin to update your Python for you,
> then you'll be able to use this:
> 
>     if some_key in adict:
> 
> 
>>   adict[some_key] += 1
>>else:
>>   adict[some_key] = 1
>>

Last I checked, both worked.

James


-- 
James Stroud
UCLA-DOE Institute for Genomics and Proteomics
Box 951570
Los Angeles, CA 90095

http://www.jamesstroud.com/