[okfn-labs] Python Iterator over table (csv) *columns*

[Edgar Zanella Alvarenga]

You can use read_csv from Pandas:

http://pandas.pydata.org/pandas-docs/version/0.13.1/generated/pandas.io.parsers.read_csv.html

usecols : array-like

     Return a subset of the columns. Results in much faster parsing time 
and lower memory usage.

and pass the columns to the `usecols` argument. If you have a problem 
with the size of
the csv file you can read it in chunks with:

pandas.read_csv(filepath, sep = DELIMITER,skiprows = 
INITIAL_LINES_TO_SKIP, chunksize = 10000)

and change the value INITIAL_LINES_TO_SKIP in your iteration.

Edgar

On 17/12/2014 05:23, Paul Walsh wrote:
> Hi,
>
> Does anyone have or know of a nice (existing) solution for iterative
> reading of CSV/table data by *column*? It needs to be an iterator - I
> don’t want everything in memory.
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