Parsing multiple values from a file in Python

Question

The file is like this:

1 118 1
1 285 3
...
39861 27196 5

So, I would like to parse the file by storing the numbers in variables, since I know apriori that every line contains three integers^*, how should I do it?

Here is my attempt:

f = open(fname, 'r')
no_of_headers = 3
for i, line in enumerate(f, no_of_headers):
  print line

Here instead of reading into line, it should be modified to read to a, b and c, since we know that every line has three numbers!

*_{Like sstream in c++}

Related Skip first couple of lines while reading lines in Python file and How can I write a csv file with multiple header lines with pandas to_csv()? — Bhargav Rao
– Bhargav Rao, Commented Apr 30, 2016 at 19:47
@BhargavRao, I can't use Pandas :/ The first link is nice, but I want to read the first three lines, not just skip them! Thanks though :) — gsamaras
– gsamaras, Commented Apr 30, 2016 at 19:50
Did you read the other answers in the first link? As you are using readlines, a couple of the answers are valid and helpful if you try to use the slice syntax there. Alternatively the enumerate answer is also helpful there. — Bhargav Rao
– Bhargav Rao, Commented Apr 30, 2016 at 19:52
@BhargavRao, I am currently doing so, yeap the enumerate should come in handy. I will update my question with a better attempt, if any. As for readlines, it's a not a must, so if there is another way, bring it on..people :) — gsamaras
– gsamaras, Commented Apr 30, 2016 at 19:54
@BhargavRao thank you very much for the links. I could narrow down the question now, discarding the part that your suggestion solved! — gsamaras
– gsamaras, Commented Apr 30, 2016 at 20:03

Akshat Mahajan · Accepted Answer · 2016-04-30 20:05:16Z

1

Just use Python's (limited) pattern recognition syntax:

for i, line in enumerate(f, no_of_headers):
    a,b,c = line.strip().split() # splits the line by whitespace

This assigns each element of the split line to a, b, c respectively. Since each line contains exactly three elements, a is mapped to the first element, b to the second, and c to the third.

answered Apr 30, 2016 at 20:05

Akshat Mahajan

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