Sort a file by first (or second, or else) column in python
The problem you're having is that you're not turning each line into a list. When you read in the file, you're just getting the whole line as a string. You're then sorting by the first character of each line, and this is always the same character in your input, 'E'
.
To just sort by the first column, you need to split the first block off and just read that section. So your key should be this:
for line in sorted(lines, key=lambda line: line.split()[0]):
split
will turn your line into a list, and then the first column is taken from that list.
If your input file is tab-separated, you can also use the csv module.
import csv
from operator import itemgetter
reader = csv.reader(open("t.txt"), delimiter="\t")
for line in sorted(reader, key=itemgetter(0)):
print(line)
sorts by first column.
Change the number in
key=itemgetter(0)
for sorting by a different column.