Append only numbers to a list from a mixed file

Question

I have a txt file which looks like this:

    100.00   gasoline
    20.00    lunch
    12.50    cigarettes

I want to take only the numbers (100.00, 20.00, 12.50) and append them to a list, how can I do it? I tried with:

    tot_us = []
    for float in us_file:
        tot_us.append(float)

When I print the list i get:

  ['100.00\tgasoline\n', '20.00\tlunch\n', '12.50\tcigarettes\n']

I was expecting:

  ['100.00', '20.00', '12.50']

I know is a noob attempt, how can I solve this?

score 0 · Accepted Answer · answered Feb 03 '16 at 15:30

0

You need to use .split() to break up each line into two sections:

total_us = []

with open('somefile.txt') as f:
    for line in f:
        if line.strip():
            bits = line.split('\t')
            total_us.append(bits[0])

print(total_us)

Or, you can use the csv module:

import csv

with open('somefile.txt') as f:
    reader = csv.reader(f, delimiter='\t')
    total_us = [row[0] for row in reader]

print(total_us)

answered Feb 03 '16 at 15:30

Burhan Khalid

169,990
18
245
284

Thanks, it worked, I then used float(i) to convert them, append them to another list and do maths. I prefer method 1 since there's no need to import anything! – RingK Feb 03 '16 at 15:50

score 0 · Answer 2 · edited May 23 '17 at 12:15

0

You could also identify the position of the tab and then use slicing:

tot_us = []
for line in us_file:
    tab_pos = line.index('\t')
    float = line[:tab_pos]
    tot_us.append(float)

For more information about slicing see this answer.

edited May 23 '17 at 12:15

Community

1
1

answered Feb 03 '16 at 15:59

simon

2,896
1
17
22

Thanks, I'll try this too, looks simpler! – RingK Feb 03 '16 at 16:28

Append only numbers to a list from a mixed file

2 Answers2