[Tutor] Change datatype for specific columns in an 2D array & computing the mean

[Peter Otten]

Ek Esawi wrote:

> Thanks for the input. Columns 2 and 3 are strings and i assume that they
> don't need to be converted. Because all i need is to compute the mean for
> data on column 4 based on each variable in column 1 and each in column 2..

I'm an amateur with numpy, and unfortunately my favourite search engine 
didn't come up with a numpy-specific way to group rows in a 2D array.

> BTW, is it possible to send you what i did off list? That way you see what
> i am doing.

No. I'm posting here to help you overcome problems you run into when 
learning Python (and sometimes the application of Python libraries), not to 
write ready-to-use code for you.