arrays - Python accesses multiple lists in a nested list. What's going wrong? -

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python doesn't support multidimensional arrays, thought workaround easy enough. it's not working though. here's code

mat = [ [ none ] * 3 ] * 3 mat[0][0] = 1 return mat 

output

[[1, none, none], [1, none, none], [1, none, none]] 

why changing mat[1][0] , mat[2][0]? if ask print mat[0][0] gives me 1 should.