Deleting a line from a file in Python

Question

I want to delete a specific line containing a specific string in Python.

Ex-

Suppose I have a file fruit.txt having the following content:

Banana

Apple

Apple1

Grapes

Now, I want to delete Apple from that file and I have made this following function:

def deleteLine():

fname = 'fruit.txt'

f = open(fname)

output = []

for line in f:

    if not "Apple" in line:

        output.append(line)

f.close()

f = open(fname, 'w')

f.writelines(output)

f.close()

It gives this output;

Banana

Apple

So, the main problem is that the function is deleting both Apple and Apple1 but I only want to delete “Apple”.

The required should be like this:

Banana

Apple1

Grapes

How should I change my function so that it gives the correct output?

Answer 1

You need to open the file and read its contents in memory, then open the file again write the line to it but without the line you wish to omit:

e.g.:

with open("yourfile.txt", "r") as f:

    lines = f.readlines()

with open("yourfile.txt", "w") as f:

    for line in lines:

        if line.strip("\n") != "nickname_to_delete":

            f.write(line)

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