If it won't be simple, it simply won't be. [source code] by Miki Tebeka, CEO, 353Solutions

Monday, May 11, 2009

Avoiding "peek" with "itertools.chain"

Sometimes you need to filter out some header information. However the only clear anchor you have is the start of real data - you need a "peek" function.

It's easy to avoid writing the "peek" logic, just use itertools.chain.

#!/usr/bin/env python
'''Avoiding the need for "peek" with itertools.chain'''

from itertools import chain

def is_first_data(line):
return line.startswith("Name:")

def skip_header(data):
data = iter(data)
for line in data:
if is_first_data(line):
return chain([line], data)

# FIXME: We might want to raise something here
return []

if __name__ == "__main__":
data = [
"this is the header",
"it might change every time",
"and you'll never find a good regexp for it",
"The first line of data is easy to know",
"Name: Duffy",
"Type: Duck",
"Anger: 10",
"Name: Bugs",
"Type: Bunny",
"Anger: 0",

data = skip_header(data)
for line in data:
print line
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