On 15 October 2015 at 09:16, Peter Otten <__pete...@web.de> wrote:
>
> def preprocess(filename):
> with open(filename) as f:
> for row in csv.reader(f):
> # do stuff
> yield row
>
> rows = preprocess("pandas.csv")
Take the with statement outside of the generator and do something like:
def preprocess(lines):
for row in csv.reader(lines):
# do stuff
yield row
with open("pandas.csv") as pandasfile:
rows = preprocess(pandasfile)
df = pandas... # etc.
This ensures that the file will be closed if an exception occurs
outside the generator or if the generator is not fully consumed.
> df = pandas.DataFrame.from_records(rows, columns=next(rows))
next(rows) can raise StopIteration which can be problematic so perhaps
something like:
try:
fieldnames = next(rows)
except StopIteration:
raise ValueError
df = pandas... (columns=fieldnames) # etc
--
Oscar
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