Find and replace within a text file using Python

问题:

I have a text file which is about 400,000 lines long. I need to import this text file into a program which only accepts text files which are delimited with spaces or tabs, but this text file is delimited with semi-colons. There is no option in the program I am exporting the text file from (Arcmap) to change the delimination and doing find and replace in the text file itself will literally take 2 days.

I have searched for a script to do this but they all seem to replace the whole LINE of the word file with a space, instead of individually replacing each semi-colon, Leaving me with an empty text file.

Here is a sample of my text file:

"OID_";"POINTID";"GRID_CODE";"POINT_X";"POINT_Y"
;1;-56.000000;200900.250122;514999.750122
;2;-56.000000;200900.750122;514999.750122
;3;-56.000000;200901.250122;514999.750122
;4;-57.000000;200901.750122;514999.750122
;5;-57.000000;200902.250122;514999.750122
;6;-57.000000;200902.750122;514999.750122
;7;-57.000000;200903.250122;514999.750122
;8;-57.000000;200903.750122;514999.750122
;9;-57.000000;200904.250122;514999.750122
;10;-57.000000;200904.750122;514999.750122

I need it to look something like this:

1 -56.000000 200900.250122 514999.750122
2 -56.000000 200900.750122 514999.750122

回答1:

How about this:

sed -i 's/;/ /g' yourBigFile.txt

This is not a Python solution. You have to start this in a shell. But if you use Notepad, I guess you are on Windows. So here a Python solution:

f1 = open('yourBigFile.txt', 'r')
f2 = open('yourBigFile.txt.tmp', 'w')
for line in f1:
    f2.write(line.replace(';', ' '))
f1.close()
f2.close()

回答2:

with Python, you can use fileinput.

import fileinput
for line in fileinput.FileInput("file",inplace=1):
    line = line.replace(";"," ")
    print line,

this will replace all your ";" to spaces in place.

回答3:

Python 3.2 has added ability to use this as context manager, so that the files that fail during processing for some reason will always get closed:

import fileinput
def main():
    with fileinput.input(inplace=True) as f:
        for line in f:
            line = line.replace(";", " ")
            print(line, end='')

(inspiration)

Use it by supplying it with the text file you want to process.