按列中的值重复文本行？

Question

I have such input (simplified to 4 columns; real data is quite huge) in tab delimited txt file:

FACTOR→NAME→SURNAME→ADDRESS
1→John→Smith→Chicago
3→Betty→Crawford→New York
2→Tom→Jonson→Chicago

And I want to get this:

FACTOR→NAME→SURNAME→ADDRESS
1→John→Smith→Chicago
3→Betty→Crawford→New York
3→Betty→Crawford→New York
3→Betty→Crawford→New York
2→Tom→Jonson→Chicago
2→Tom→Jonson→Chicago

In other words: I want to repeat each row based on value in FACTOR column. This value can have only number > 0 . How can I do this in Python?

Answer 1

You can create an output.txt file for this, and considering the above mentioned lines as part of a input.txt , you can do something like:

inp = open('input.txt', 'r')
lines = inp.readlines()
inp.close()

out = open('output.txt', 'w')
for line in lines:
    factor = int(line.split('\t')[0]) #splits on tab and gets the leftmost value, converts it to int
    out.write(line+'\n'*factor) #this writes the line desired number of times
out.close()

Answer 2

With script provided by Sam Chats I got this error: ValueError: invalid literal for int() with base 10: 'FACTOR' I guess it was because column name FACTOR was also used in loop as multiplying factor. I did some modifications to script and I got what I needed:

inp = open('input.txt', 'r')
out = open('output.txt', 'w')
header = inp.readline()
lines = inp.readlines()[0:]

out.write(header)

for line in lines:
    factor = int(line.split('\t')[0])
    out.write(line*factor)

inp.close()
out.close()

Thanks for the tips!