python csv reader, loop from the second row

Question

In python 2.7.3, how can I start the loop from the second row? e.g.

first_row = cvsreader.next();
for row in ???: #expect to begin the loop from second row
    blah...blah...

I should test the most obvious way before ask, this is a stupid question :( — GuLearn
– GuLearn, Commented May 3, 2013 at 2:23
@user2207811 I'm glad you asked it, because up until now I've been doing something like enumerate(cvsreader) ... if index > 0: .... :) — Wesley Baugh
– Wesley Baugh, Commented May 3, 2013 at 2:28
I second Wesley's comment -- specifically the "glad you asked" part. And thank you, Wesley, for answering -- and so quickly. — mechanical_meat
– mechanical_meat, Commented May 3, 2013 at 2:29

jamylak · Accepted Answer · 2013-05-03 02:30:27Z

25

first_row = next(csvreader)  # Compatible with Python 3.x (also 2.7)
for row in csvreader:  # begins with second row
    # ...

Testing it really works:

>>> import csv
>>> csvreader = csv.reader(['first,second', '2,a', '3,b'])
>>> header = next(csvreader)
>>> for line in csvreader:
    print line
['2', 'a']
['3', 'b']

edited May 3, 2013 at 2:30

jamylak

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answered May 3, 2013 at 2:05

Wesley Baugh

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1 Comment

Blender Over a year ago

.next() was removed in Python 3. I'd use next(csvreader).

jamylak · Accepted Answer · 2013-05-03 02:35:58Z

4

next(reader, None) # Don't raise exception if no line exists

looks most readable IMO

The other alternative is

from itertools import islice
for row in islice(reader, 1, None)

However shouldn't you be using the header? Consider a csv.DictReader which by default sets the fieldnames to the first line.

answered May 3, 2013 at 2:35

jamylak

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1 Comment

GuLearn Over a year ago

Thank you for mentioning the alternative! I'm not using the header because the specific csv file I'm dealing with has an empty header :P

Pedro Lobito · Accepted Answer · 2017-03-07 19:15:10Z

0

Assuming the 1st row contains the field names:

import csv
for field in csv.DictReader(open("./lists/SP500.csv", 'rb')):
    symbol = (field['ticker']).rstrip()

answered Mar 7, 2017 at 19:15

Pedro Lobito

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