Can Python remove double quotes from a string, when reading in text file?

问题

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]

回答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

回答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.

回答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']

回答4:

for line in open(fname):
    line = line.split()
    line[-1] = line[-1].strip('"\n')
    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]

回答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))

回答6:

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

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

回答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! :)

回答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.

回答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']

来源：https://stackoverflow.com/questions/1707558/can-python-remove-double-quotes-from-a-string-when-reading-in-text-file