Question

I have some text file like this, with several 5000 lines:

5.6  4.5  6.8  "6.5" (new line)
5.4  8.3  1.2  "9.3" (new line)

so the last term is a number between double quotes.

What I want to do is, using Python (if possible), to assign the four columns to double variables. But the main problem is the last term, I found no way of removing the double quotes to the number, is it possible in linux?

This is what I tried:

#!/usr/bin/python

import os,sys,re,string,array

name=sys.argv[1]
infile = open(name,"r")

cont = 0
while 1:
         line = infile.readline()
         if not line: break
         l = re.split("s+",string.strip(line)).replace( " ,  )
     cont = cont +1
     a = l[0]
     b = l[1]
     c = l[2]
     d = l[3]

Answer 1

The csv module (standard library) does it automatically, although the docs isn t very specific about skipinitialspace

>>> import csv

>>> with open(name,  rb ) as f:
...     for row in csv.reader(f, delimiter=   , skipinitialspace=True):
...             print  | .join(row)

5.6|4.5|6.8|6.5
5.4|8.3|1.2|9.3

Answer 2

for line in open(name, "r"):
    line = line.replace( " ,   ).strip()
    a, b, c, d = map(float, line.split())

This is kind of bare-bones, and will raise exceptions if (for example) there aren t four values on the line, etc.

Answer 3

There s a module you can use from the standard library called shlex:

>>> import shlex
>>> print shlex.split( 5.6  4.5  6.8  "6.5" )
[ 5.6 ,  4.5 ,  6.8 ,  6.5 ]

Answer 4

for line in open(fname):
    line = line.split()
    line[-1] = line[-1].strip( "
 )
    floats = [float(i) for i in line]

another option is to use built-in module, that is intended for this task. namely csv:

>>> import csv
>>> for line in csv.reader(open(fname), delimiter=   ):
    print([float(i) for i in line])

[5.6, 4.5, 6.8, 6.5]
[5.6, 4.5, 6.8, 6.5]

Answer 5

Or you can simply replace your line

l = re.split("s+",string.strip(line)).replace( " ,  )

with this:

l = re.split( [s"]+ ,string.strip(line))

Answer 6

I used in essence to remove the " in "25" using

Code:
        result = result.strip(""") #remove double quotes characters

Answer 7

I think the easiest and most efficient thing to do would be to slice it!

From your code:

d = l[3]
returns "6.5"

so you simply add another statement:

d = d[1:-1]

now it will return 6.5 without the leading and end double quotes.

viola! :)

Answer 8

You can use regexp, try something like this

import re
re.findall("[0-9.]+", file(name).read())

This will give you a list of all numbers in your file as strings without any quotes.

Answer 9

IMHO, the most universal doublequote stripper is this:

In [1]: s =  1 " 1 2" 0 a "3 4 5 " 6 
In [2]: [i[0].strip() for i in csv.reader(s, delimiter=   ) if i != [  ,   ]]
Out[2]: [ 1 ,  1 2 ,  0 ,  a ,  3 4 5 ,  6 ]

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