How do I take in Command Line arguments?

[ironmonkey69]

Right now, I have this python script that lets me choose which column of a text file that I can zero out. Them column nubmer is stored as the variable 'elem'. I also was given a sample of taking in command line arguements. I was wondering if anyone could help me intergrate this into the code so that from the command line I can input a number and have the script zero out the column.

beginning text file:
#Number of Bits
12
#Data
0 0 0 0 0 0 0 0 0 0 0 0
12 5 3 4 6 4 5 4 7 5 5 10
24 9 7 7 13 7 9 9 14 10 10 20

text file after script has been run:
#Number of Bits
12
#Data
0 0 0 0 0 0 0 0 0 0 0 0
0 5 3 4 6 4 5 4 7 5 5 10
0 9 7 7 13 7 9 9 14 10 10 20
and this is what it does:

def nthzero(dataList, nth, n):
    '''
    Replace the nth element of each list in the data list with 'n'
    '''
    for item in dataList:
        item[nth] = n
    return dataList
 
fn = '/outfile.txt'
f = open(fn)
 
s = f.readline()
prefix = s
while s.strip() != '#Data':
    s = f.readline()
    prefix += s
 
lineList = [line.strip().split() for line in f.readlines()]
for line in f.readlines():
    lineList.append(line.strip().split())
 
f.close()
elem = 0
repl = '0'
lineList = nthzero(lineList, elem, repl)
 
fn1 = '/outfile.txt'
f = open(fn1, 'w')
outList = []
for line in lineList:
    outList.append(' '.join(line))
 
f.write('%s%s' % (prefix, '\n'.join(outList)))
f.close()
 

example of the command line

/usr/bin/python hello.py \"1, 2, 4, 6, 9\""
 
hello.py
import sys
names = sys.argv[1].split(', ')
list = []
for name in names:
   list.append(name)
print list
#print "Hello " + sys.argv[1]
 
output:
Hello [1, 2, 4, 6, 9]
 

[ironmonkey69]

This code is in Python 2.0.

[bartonc]

/usr/bin/python hello.py 1 2 4 6 9

[eric dexter]

I have a couple of examples that I have been distributing one is in tracker8.py available in my dex tracker project (url at bottom). What I did was use a main function. The code you are writing looks like it would be usefull for what I am doing and maybe something that would allow a series of numbers from a file into the column you are zeroing out might be a good contribution to my project :) ... http://www.stormpages.com/edexter/csound.html

[eric dexter]

Right now, I have this python script that lets me choose which column of a text file that I can zero out. Them column nubmer is stored as the variable 'elem'. I also was given a sample of taking in command line arguements. I was wondering if anyone could help me intergrate this into the code so that from the command line I can input a number and have the script zero out the column.

beginning text file:
#Number of Bits
12
#Data
0 0 0 0 0 0 0 0 0 0 0 0
12 5 3 4 6 4 5 4 7 5 5 10
24 9 7 7 13 7 9 9 14 10 10 20

text file after script has been run:
#Number of Bits
12
#Data
0 0 0 0 0 0 0 0 0 0 0 0
0 5 3 4 6 4 5 4 7 5 5 10
0 9 7 7 13 7 9 9 14 10 10 20
and this is what it does:

def nthzero(dataList, nth, n):
    '''
    Replace the nth element of each list in the data list with 'n'
    '''
    for item in dataList:
        item[nth] = n
    return dataList
 
fn = '/outfile.txt'
f = open(fn)
 
s = f.readline()
prefix = s
while s.strip() != '#Data':
    s = f.readline()
    prefix += s
 
lineList = [line.strip().split() for line in f.readlines()]
for line in f.readlines():
    lineList.append(line.strip().split())
 
f.close()
elem = 0
repl = '0'
lineList = nthzero(lineList, elem, repl)
 
fn1 = '/outfile.txt'
f = open(fn1, 'w')
outList = []
for line in lineList:
    outList.append(' '.join(line))
 
f.write('%s%s' % (prefix, '\n'.join(outList)))
f.close()
 

example of the command line

/usr/bin/python hello.py \"1, 2, 4, 6, 9\""
 
hello.py
import sys
names = sys.argv[1].split(', ')
list = []
for name in names:
   list.append(name)
print list
#print "Hello " + sys.argv[1]
 
output:
Hello [1, 2, 4, 6, 9]
 

I haven't tried this yet but another way to write your program may be to use vim as a com object (with pywin or maybe through wxpython). There was a recent post on the vim board that describes a way to insert a column...

http://groups.google.com/group/vim-experiment/browse_thread/thread/447a01d7014be5c9

This has all been pretty tempting but I have been coding other stuff

[bvdet]

Right now, I have this python script that lets me choose which column of a text file that I can zero out. Them column nubmer is stored as the variable 'elem'. I also was given a sample of taking in command line arguements. I was wondering if anyone could help me intergrate this into the code so that from the command line I can input a number and have the script zero out the column.

beginning text file:
#Number of Bits
12
#Data
0 0 0 0 0 0 0 0 0 0 0 0
12 5 3 4 6 4 5 4 7 5 5 10
24 9 7 7 13 7 9 9 14 10 10 20

text file after script has been run:
#Number of Bits
12
#Data
0 0 0 0 0 0 0 0 0 0 0 0
0 5 3 4 6 4 5 4 7 5 5 10
0 9 7 7 13 7 9 9 14 10 10 20
and this is what it does:

def nthzero(dataList, nth, n):
    '''
    Replace the nth element of each list in the data list with 'n'
    '''
    for item in dataList:
        item[nth] = n
    return dataList
 
fn = '/outfile.txt'
f = open(fn)
 
s = f.readline()
prefix = s
while s.strip() != '#Data':
    s = f.readline()
    prefix += s
 
lineList = [line.strip().split() for line in f.readlines()]
for line in f.readlines():
    lineList.append(line.strip().split())
 
f.close()
elem = 0
repl = '0'
lineList = nthzero(lineList, elem, repl)
 
fn1 = '/outfile.txt'
f = open(fn1, 'w')
outList = []
for line in lineList:
    outList.append(' '.join(line))
 
f.write('%s%s' % (prefix, '\n'.join(outList)))
f.close()
 

example of the command line

/usr/bin/python hello.py \"1, 2, 4, 6, 9\""
 
hello.py
import sys
names = sys.argv[1].split(', ')
list = []
for name in names:
   list.append(name)
print list
#print "Hello " + sys.argv[1]
 
output:
Hello [1, 2, 4, 6, 9]
 

At the command line: python code.py 1 2 4 6 9

Assign the following to variable 'elem':

elem = [int(i) for i in sys.argv[1:]]

Following is the code I used:

import sys
 
def nthzero(dataList, nthList, n):
    '''
    Replace the nth element of each list in dataList with 'n'
    '''
    for nth in nthList:
        for item in dataList:
            try:
                item[nth] = n
            except IndexError, e:
                pass
    return dataList
 
if __name__ == '__main__':
 
    fn = 'datain.txt' 
    f = open(fn) 
 
    s = f.readline()
    prefix = s
    while s.strip() != '#Data':
        s = f.readline()
        prefix += s
 
    lineList = [line.strip().split() for line in f.readlines()] 
 
    f.close() 
    #elem = [1,2,3,4,8,9,15]
 
    # Command Line
    # C:\Python23>python nthzero.py 1 2 3 4 8 9 15
    elem = [int(i) for i in sys.argv[1:]]
 
    repl = '0' 
    lineList = nthzero(lineList, elem, repl) 
 
    fn1 = 'dataout.txt' 
    f = open(fn1, 'w')
 
    outList = []
 
    for line in lineList:
        outList.append(' '.join(line))
 
    f.write('%s%s' % (prefix, '\n'.join(outList)))
    f.close()

[ironmonkey69]

this script takes in numbers one at a time eventhough they are listed together. Is there a way that I can input an entire list, i.e. 0 1 2 3 4 5, from the command line and have the script zero them out? Kinda like the example:

import sys
names = sys.argv[1].split(', ')
list = []
for name in names:
    list.append(name)
print list
#print "Hello " + sys.argv[1]
 

[bartonc]

this script takes in numbers one at a time eventhough they are listed together. Is there a way that I can input an entire list, i.e. 0 1 2 3 4 5, from the command line and have the script zero them out? Kinda like the example:

import sys
names = sys.argv[1].split(', ')
list = []
for name in names:
    list.append(name)
print list
#print "Hello " + sys.argv[1]
 

You can put quotes around your command-line argument: "1, 2, 3" (I think).

[ironmonkey69]

As I said before, I am a noob at python and am trying to understand what is going on. I was wondering if you help me understand what a couple of the lines of the script are doing.

 lineList = [line.strip().split() for line in f.readlines()]
 

[ironmonkey69]

how does this script work?

[bartonc]

As I said before, I am a noob at python and am trying to understand what is going on. I was wondering if you help me understand what a couple of the lines of the script are doing.

 lineList = [line.strip().split() for line in f.readlines()]
 

That's called a list comprehension. In order to understand it, let's break it down:

tempList = f.readlines()
lineList = []
for line in tempList:
    newLine = line.strip()
    print newLine
    wordList = newLine.split()
    print wordList
    lineList.append(wordList)
print lineList

Does that help?

[ironmonkey69]

it helps a little more. Can you add some comments to the code to help me get a better a better understanding of which sections do what?