Python：删除特定字符（，）之后的所有内容

Question

I have millions of lines inside a file (9GB)(can't opened by Notepad++) and i want to remove all the words after a specific characters. (,)

Example of line :

data1,data2,data3,data4

I want to keep the (data1) and delete everything else.

Thanks in advance.

Answer 1

You can use split on each line to split the line on the first comma and only write out the left part of the split:

For example:

with open('input.txt') as infile:
    with open('output.txt','w') as outfile:
        for line in infile.readline():
            outfile.write(line.strip().split(",",1)[0]+"\n")