Python: Replace multiple strings in text file with multiple inputs

Question

I am looking at replacing multiple strings with input from the user. The following code (which is a modification of a code from one of the queries here in stackoverflow; pardon coz I can't find the thread anymore) works well when finding and replacing one instance(done on purpose) of a specified string:

print('What word should we replace s1 with?')
input_1 = input()
with open('C:\\dummy1.txt')as f:
     sample1 = f.read().replace("s1", str(input_1), 1)
with open('C:\\dummy2.txt',"w") as f1:
     f1.write(sample1)

Now when I try copy-pasting the same and modifying it to cater to other strings, only the last specified string gets replaced... here's a sample code:

print('What word should we replace s1 with?')
input_1 = input()
with open('C:\\dummy1.txt')as f:
     sample1 = f.read().replace("s1", str(input_1), 1)
with open('C:\\dummy2.txt',"w") as f1:
     f1.write(sample1)

print('What word should we replace s2 with?')
input_2 = input()
with open('C:\\dummy1.txt')as f:
     sample2 = f.read().replace("s2", str(input_2), 1)
with open('C:\\dummy2.txt',"w") as f1:
     f1.write(sample2)

What do I need to do to make this work seamlessly for multiple strings? Please consider explaining it to someone with less than a year experience in coding and 9-hour worth of video learning in python :) Thank you!

Is there a reason you don't get both inputs and then replace s1 and s2 at the same time so you aren't opening and closing more than needed? — SuperStew
– SuperStew, Commented Nov 1, 2017 at 14:41

SuperStew · Accepted Answer · 2017-11-01 15:10:37Z

2

This worked for me.

#using os to get path since py and txt file are in same folder
#just change your actual path if you need
import os
curdir=os.getcwd()
filepath=os.path.join(curdir,'the_file.txt')


print('What word should we replace s1 with?')
input_1 = input()
print('What word should we replace s2 with?')
input_2 = input()

sample1=''
sample2=''
with open(filepath, 'r')as f:
     sample1 = f.read().replace("s1", str(input_1), 1)
     sample2 = sample1.replace("s2", str(input_2), 1)
with open(filepath, 'w')as f:    
     f.write(sample2)

EDIT:

Also I just realized than you read from dummy1.txt and write to dummy2.txt both times that you get inputs and replace text. That's the reason that only s2 is being changed. You should read from dummy2.txt when changing s2 because that is the file that contains the s1 change. In my example above I just overwrite the file I read from, but that's easily changed if you want.

    #using os to get path since py and txt file are in same folder
#just change your actual path if you need
import os
curdir=os.getcwd()
filepath=os.path.join(curdir,'the_file.txt')
filepath_2=os.path.join(curdir,'the_other_file.txt')


print('What word should we replace s1 with?')
input_1 = input()
print('What word should we replace s2 with?')
input_2 = input()

sample1=''
sample2=''
with open(filepath, 'r')as f:
     sample1 = f.read().replace("s1", str(input_1), 1)
     sample2 = sample1.replace("s2", str(input_2), 1)
with open(filepath_2, 'w')as f:    
     f.write(sample2)

edited Nov 1, 2017 at 15:10

answered Nov 1, 2017 at 14:57

SuperStew

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4 Comments

jNsatiable Over a year ago

OMG, thank you! Just one minor issue, how do I get it to save as another file (renamed)? The original file will be used multiple times so it has to remain unchanged,.. sorry for the total noobishness haha

SuperStew Over a year ago

You can simply make a "filepath_2" or something, see edit

jNsatiable Over a year ago

Ooops, I just figured it out. Thank you SuperStew :)

jNsatiable Over a year ago

Your post comment sure is enlightening :)

Matt Pitkin · Accepted Answer · 2017-11-01 14:42:26Z

0

I think what you want is, in the second instance, to open the file C:\\dummy2.txt file in append mode rather than write mode (which overwrites any previous output), e.g., use open('C:\\dummy2.txt',"a") rather than open('C:\\dummy2.txt',"w")

answered Nov 1, 2017 at 14:42

Matt Pitkin

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1 Comment

jNsatiable Over a year ago

Thanks for answering, Matt. I appreciate it :)

Temi Fakunle · Accepted Answer · 2017-11-01 16:09:42Z

0

For a shorter code, you could get both strings at once and chain the replace method:

replacement_strings = input('Please enter S1 and S2, separated by hyphen :').split('-')
with open('C:\\dummy1.txt')as f:
    sample1 = f.read().replace("s1", replacement_strings[0]).replace("s2", replacement_strings[1]) if len(replacement_strings) > 1 else f.read().replace("s1", replacement_strings[0]) if replacement_strings
with open('C:\\dummy2.txt',"w") as f1:
    f1.write(sample1)

Note: For python 2.x, you would need to use raw_input() instead of input()

answered Nov 1, 2017 at 16:09

Temi Fakunle

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2 Comments

jNsatiable Over a year ago

Hey! This idea of putting all together in a single input is awesome! I could certainly use it but I fear this code is incomplete? PS: Would love to upvote but still can't coz <15 rep and stuff XD

jNsatiable Over a year ago

Oh, I just deleted the if and else parts and it worked like a charm. Thanks a lot for this code, @TemiFakunle !

jlanssie · Accepted Answer · 2019-11-13 19:42:15Z

I found a way to easily find-replace multiple strings in Python.

In this example, find[0] is replaced by replace[0] etc.

The statement "x = line.replace(find[0], replace[0]).replace(find[1], replace[1])..." is dynamically created as a string, and later this string is executed.

I used this script transform a word docx into an HTML file and then change multiple strings in that HTML file.

import mammoth
import os
import fileinput    

#set source, output
source = 'test.docx'
output = 'output.html'    

#set find and replace, e.g. find[0] will be replaced by replace[0]
find = ['a', '1']
replace = ['b', '2']    

#convert to html in temp file
temp = '.temp.html'
f = open(source, 'rb')
b = open(temp, 'wb')
document = mammoth.convert_to_html(f)
b.write(document.value.encode('utf8'))
f.close()
b.close()    

#create a find-and-replace statement
i = 0
c = len(find)
string = "x = line"
while i < c: 
    x = ".replace(find[" + str(i) + "], replace[" + str(i) + "])"
    string = string + x
    i = i + 1    

#write output file
f = open(output, 'wb')
with fileinput.FileInput(temp, inplace=False, openhook=fileinput.hook_encoded('utf-8', 'surrogateescape')) as file:
    for line in file:
        #execute the find-and-replace statement
        exec(string)
        f.write(x.encode('utf-8'))
f.close()    

#remove temp file
os.remove(temp)

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