CODEWITHSUNDEEP
python
thclpr
thclpr

Reputation: 5938

Replace text in a file

Its pretty simple, with the small code bellow, i can read a file and match where i can find the musicStyle field and replace the value with something else and write the changes on the file. Its a xml and i know that i could use lxml or other xml parser, but i want to keep using the re module because is nothing huge, its for my personal database of music collection.

import re

def replace(theFile):
    #for iLine in (line.rstrip('\n') for line in open(theFile,"w")):
        if iLine.find("musicStyle") >= 0:
            mpr = re.search(r'(.*>)(.*?)(<.*)', iLine, re.M|re.I)
            print mpr.group(2)
            # here goes the code to replace the mpr.group(2) 
            # should i use iLine.replace('rock','Metal') ?

if __name__ == '__main__':
    replace('c:\testfile.xml')

Thanks in advance.

Upvotes: 1

Views: 91

Answers (3)

thclpr
thclpr

Reputation: 5938

I was able to solve it with:

import re

def replace(theFile):
    for line in fileinput.input(theFile,inplace=1):
        if line.find("musicStyle") >= 0:
           mpr = re.search(r'(.*>)(.*?)(<.*)', line, re.M|re.I)
           line = line.replace("rock","metal")
        print line,


if __name__ == '__main__':
    replace('c:\\testfile.xml')

i had to put a comma on line in order to avoid new lines on the file.

Thanks Ashwini for the direction.

Upvotes: 0

Ashwini Chaudhary
Ashwini Chaudhary

Reputation: 250881

Use the fileinput module if you're trying to modify the same file:

import fileinput
for iLine in filinput.input(r'c:\testfile.xml',inplace = True):
    if iLine.find("musicStyle") >= 0:
         mpr = re.search(r'(.*>)(.*?)(<.*)', iLine, re.M|re.I)
         #modify iLine here
    print iLine     #write the line to  the file

Note that when you're using windows paths always use raw string, otherwise this will happen:

>>> print 'c:\testfile.xml'
c:  estfile.xml            #'\t' converted to tab space

>>> print r'c:\testfile.xml'   #raw string works fine
c:\testfile.xml

Upvotes: 2

uzi
uzi

Reputation: 5143

Honestly, the best thing to do would be to write the output to a separate temporary file, then move the file in place of the original file.

Upvotes: 0

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