Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #97413

Re: Finding Blank Columns in CSV

Show all headers | View raw

On Tue, Oct 6, 2015 at 12:48 AM, Chris Angelico <rosuav@gmail.com> wrote:
> fn = "tmp1.csv"
> fin = open(fn, 'rb')
> rdr = csv.DictReader(fin, delimiter=',')
> # all the same down to here
> blanks = set(rdr.fieldnames)
> for row in data:
>     blanks = {col for col in blanks if not row[col]}
> mt = [col for col in rdr.fieldnames if col not in blanks]
> print mt

Oops, premature send - hadn't proofread it yet.

fn = "tmp1.csv"
fin = open(fn, 'rb')
rdr = csv.DictReader(fin, delimiter=',')
# all the same down to here
blanks = set(rdr.fieldnames)
for row in rdr:
    blanks = {col for col in blanks if not row[col]}
mt = [col for col in rdr.fieldnames if col not in blanks]
print mt

Though I still haven't tested it, so there may be other bugs. Broadly
speaking, though, what it does is quite simple: start by assuming that
every column is nothing but blanks, and then any time you find a
non-blank cell, remove it from the set of blanks. At the end, all
field names not present in the set of blanks are non-blanks.

ChrisA

Back to comp.lang.python | Previous | Next | Find similar | Unroll thread

Thread

Re: Finding Blank Columns in CSV Chris Angelico <rosuav@gmail.com> - 2015-10-06 00:51 +1100

csiph-web