Tuesday, September 15, 2009

Find text string in file in Python

Each line of file "querymapping.txt" contains two fields.
1st field is a sql query and
2nd one is a filename where the output of that sql query is stored.

$ cat querymapping.txt
select * from tab_fan_details;|/tmp/query7
select * from tab_fan_speed_details;|/tmp/query4
select * from tab_fan_spec;|/tmp/query1


Write a python function to look-up a particular sql query (send as 1st argument to the script ) in the querymapping.txt file and return the query output filename. If no match found return default filename as '/tmp/query0'

The python program:

import sys

def lookupfilename(query):
'''Lookup query output filename from query'''
for line in open('querymapping.txt'):
if query.strip() in line.strip().split("|")[0]:
return line.strip().split("|")[1]
return default

print fname

Executing the script:

$ python qlookup.py "select * from tab_fan_speed_details;"

$ python qlookup.py "select * from tab_fan_speed_details_new;"

Related post:

- Lookup file in python using dictionary