How to delete all characters after a “==” in each line of a file and update the file, using python script?

Question

I have a huge list of python packages that had been installed saved with the version numbers in the file "foo.txt", I want to delete the "==" and whatever after that in each lines, and save the file.

example text in the file:

autopep8==1.5.3
beautifulsoup4==4.8.2
bleach==3.1.4
bumpversion==0.5.3
... etc

Answer 1

Use the below code.

read that file and store it in list named pkg_list.

output_lst = []
with open("input.txt", "r") as f:
    input_data = f.readlines()
    output_lst = [name.split("==")[0] for name in input_data]

with open("input.txt", "w") as f:
    for pkg in output_lst:
        f.write("{}\n".format(pkg))

Answer 2

Use this line of code if you want to create a new file with updated data, if you want to just read use the data then make changes accordingly.

def read_write_file(input_path, output_path):
    with open(input_path, "r") as input_file:
        content = input_file.readlines()

    with open(output_path, 'w') as output_file:
        for line in content:
            line = line[:line.find('==')]
            output_file.write(line + '\n')