On 9/8/2010 2:55 PM, Jonno wrote:
I know that I can index into a list of lists like this:
a=[[1,2,3],[4,5,6],[7,8,9]]
a[0][2]=3
a[2][0]=7
but when I try to use fancy indexing to select the first item in each
list I get:
a[0][:]=[1,2,3]
a[:][0]=[1,2,3]
Why is this and is there a way to select [1,4,7]?
You are trying to look at a list of lists as an array and have
discovered where the asymmetry of the former makes the two
non-equivalent. To slice multi-dimensional arrays any which way, you
need an appropriate package, such as numpy.
--
Terry Jan Reedy
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