Python - Way to recursively find and replace string in text files

Question

I want to recursively search through a directory with subdirectories of text files and replace every occurrence of {$replace} within the files with the contents of a multi l

Answer 1

How about just using:

clean = ''.join([e for e in text if e != 'string'])

Answer 2

Sulpy's answer is good but incomplete. The user would be likely to want to input the parameters through an entry widget, so we might have something more like this (also incomplete, but left as an exercise):

import os, fnmatch
from Tkinter import *
fields = 'Folder', 'Search', 'Replace', 'FilePattern'

def fetch(entvals):
#    print entvals
#    print ents
    entItems = entvals.items()
    for entItem in entItems:
        field = entItem[0]
        text  = entItem[1].get()
        print('%s: "%s"' % (field, text))

def findReplace(entvals):
#    print ents
    directory = entvals.get("Folder").get()
    find = entvals.get("Search").get()
    replace = entvals.get("Replace").get()
    filePattern = entvals.get("FilePattern").get()
    for path, dirs, files in os.walk(os.path.abspath(directory)):
        for filename in fnmatch.filter(files, filePattern):
#            print filename
            filepath = os.path.join(path, filename)
            print filepath  # Can be commented out --  used for confirmation
            with open(filepath) as f:
                s = f.read()
            s = s.replace(find, replace)
            with open(filepath, "w") as f:
                f.write(s)

def makeform(root, fields):
    entvals = {}
    for field in fields:
        row = Frame(root)
        lab = Label(row, width=17, text=field+": ", anchor='w')
        ent = Entry(row)
        row.pack(side=TOP, fill=X, padx=5, pady=5)
        lab.pack(side=LEFT)
        ent.pack(side=RIGHT, expand=YES, fill=X)
        entvals[field] = ent
#        print ent
    return entvals

if __name__ == '__main__':
    root = Tk()
    root.title("Recursive S&R")
    ents = makeform(root, fields)
#    print ents
    root.bind('<Return>', (lambda event, e=ents: fetch(e)))
    b1 = Button(root, text='Show', command=(lambda e=ents: fetch(e)))
    b1.pack(side=LEFT, padx=5, pady=5)
    b2 = Button(root, text='Execute', command=(lambda e=ents: findReplace(e)))
    b2.pack(side=LEFT, padx=5, pady=5)
    b3 = Button(root, text='Quit', command=root.quit)
    b3.pack(side=LEFT, padx=5, pady=5)
    root.mainloop()

Answer 3

Here's my code (which I think is the same as the above but I'm including it just in case there's something subtly different about it):

import os, fnmatch, sys
def findReplace(directory, find, replace, filePattern):
    for path, dirs, files in os.walk(os.path.abspath(directory)):
        for filename in fnmatch.filter(files, filePattern):         
            filepath = os.path.join(path, filename)
            with open(filepath) as f:
                s = f.read()
            s = s.replace(find, replace)
            with open(filepath, "w") as f:
                f.write(s)

it runs without error. BUT, the file, in z:\test is unchanged. I've put in print statements, like print("got here") but they don't print out either.

Answer 4

Multiple files string change

import glob

for allfiles in glob.glob('*.txt'):

for line in open(allfiles,'r'):
    change=line.replace("old_string","new_string")
    output=open(allfiles,'w')
    output.write(change)    

Answer 5

For those using Python 3.5+ you can now use a glob recursively with the use of ** and the recursive flag.

Here's an example replacing hello with world for all .txt files:

for filepath in glob.iglob('./**/*.txt', recursive=True):
    with open(filepath) as file:
        s = file.read()
    s = s.replace('hello', 'world')
    with open(filepath, "w") as file:
        file.write(s)

Answer 6

os.walk is great. However, it looks like you need to filer file types (which I would suggest if you are going to walk some directory). To do this, you should add import fnmatch.

import os, fnmatch
def findReplace(directory, find, replace, filePattern):
    for path, dirs, files in os.walk(os.path.abspath(directory)):
        for filename in fnmatch.filter(files, filePattern):
            filepath = os.path.join(path, filename)
            with open(filepath) as f:
                s = f.read()
            s = s.replace(find, replace)
            with open(filepath, "w") as f:
                f.write(s)

This allows you to do something like:

findReplace("some_dir", "find this", "replace with this", "*.txt")