using zip for transpose
Robin Becker
robin at reportlab.com
Thu Feb 21 09:39:06 EST 2019
On 21/02/2019 13:49, Peter Otten wrote:
> Robin Becker wrote:
>
>.......
> Isn't df.values a numpy array? Then try the more direct and likely more
> efficient
>
> df.values.tolist()
>
> or, if you ever want to transpose
>
> df.values.T.tolist()
>
> The first seems to achieve what your sample code does. (In addition it also
> converts the numpy type to the corresponding python builtin, i. e.
> numpy.float64 becomes float etc.)
>
Thanks for the pointer.
In fact we were working through all the wrong methods eg iterrows (slow) or iterating over columns which created the need for a
transpose.
However, df.values.tolist() seems to create a list of row lists which is what is actually needed and it is the fastest.
So to convert df to something for reportlab table this seems most efficient
rlab_table_data=[['Mean','Max','Min','TestA','TestB']]+df.values.tolist()
thanks again
--
Robin Becker
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