Question

I have two tab delimited files, file 1 contains identifiers and file 2 has values related to these identifiers (or say it is a very big dictionary).

file 1

Ronny
Rubby
Suzie
Paul

file 1 has only one column.

file 2

Alistar Barm Cathy Paul Ronny Rubby Suzie Tom Uma Vai Zai
12      13    14   12     11   11   12    23 30  0.34 0.65
1       4     56   23     12   8.9  5.1   1  4    25  3

n number of rows are present in file 2.

what I want, if the identifiers of file 1 are present in file 2, I should have all the values related to it in an another tab delimited file.

Something like this:

Paul Ronny Rubby Suzie
12     11   11   12
23     12   8.9  5.1

Thank you in advance.

Answer 1

An example in Python that does the work in stream (ie: don’t need to load the full file before starting the output):

# read keys
with open('file1', 'r') as fd:
    keys = fd.read().splitlines()

# output keys
print '\t'.join(keys)

# read data file, with header line and content
with open('file2', 'r') as fd:
    headers = fd.readline().split()
    while True:
        line = fd.readline().split()
        if len(line) == 0:
            break
        print '\t'.join([line[headers.index(x)] for x in keys if x in headers])

Output:

$ python test.py 
Ronny   Ruby    Suzie   Paul
11      11      12      12
12      8.9     5.1     23