Split string, ignoring delimiter within quotation marks (python)

Question

I would like to split a string on a comma, but ignore cases when it is within quotation marks:

for example:

teststring = '48, "one, two", "2011/11/03"'
teststring.split(",")
['48', ' "one', ' two"', ' "2011/11/03"']

and the output I would like is:

['48', ' "one, two"', ' "2011/11/03"']

Is this possible?

Answer 1

The csv module will work if you set options to handle this dialect:

>>> import csv
>>> teststring = '48, "one, two", "2011/11/03"'
>>> for line in csv.reader([teststring], skipinitialspace=True):
    print line


['48', 'one, two', '2011/11/03']

Answer 2

You can use the csv module from the standard library:

>>> import csv
>>> testdata = ['48, "one, two", "2011/11/03"']
>>> testcsv = csv.reader(testdata,skipinitialspace=True)
>>> testcsv.next()
['48', 'one, two', '2011/11/03']

The one thing to watch out for is that the csv.reader objects expect an iterator which will return a string each time next() is called. This means that you can't pass a string string straight to a reader(), but you can enclose it in a list as above.

You'll have to be careful with the format of your data or tell csv how to handle it. By default the quotes have to come immediately after the comma or the csv module will interpret the field as beginning with a space rather than being quoted. You can fix this using the skipinitialspace option.