How to present a[ a [ : , 0] > 0 , : ] ?

[CNWindson]

An ez question, wish your reply XD!

[dpilger26]

a(a(a.rSlice(), 0) > 0, a.cSlice())

[CNWindson]

a(a(a.rSlice(), 0) > 0, a.cSlice())

Oops，it breaks an error like: no match 'operator>' （operand types are 'nc::NdArray' and 'int') @dpilger26

[dpilger26]

Sorry, NumCpp doesn't currently have an operator() overload for a mask slice such as your question (I'll have to add that into the next release). The way you would need to do your example currently would be slightly more verbose where you actually extract the index values:

#include "NumCpp.hpp"

#include <cstdlib>
#include <iostream>

int main ()
{
    nc::random::seed(7);

    auto a = nc::random::randInt<int>({10, 10}, -10, 10);
    std::cout << a << '\n';

    auto b = a(nc::nonzero(a(a.rSlice(), 0) > 0).first, a.cSlice());
    std::cout << b;

    return EXIT_SUCCESS;
}

which outputs:

[[5, 8, -8, 7, -8, -9, 6, 8, -5, 4, ]
[5, 1, -3, -4, 6, -4, 9, 9, 7, -5, ]
[2, -5, -10, -10, -8, -7, -3, -4, 3, 2, ]
[0, -10, -5, 4, -2, 7, 3, -5, -7, 5, ]
[-8, 1, 1, -4, -10, 1, -4, -8, 3, 9, ]
[-7, 0, 1, 3, -5, -10, 4, -9, -5, -9, ]
[-9, 5, 0, -4, -6, -7, 3, -8, 5, -9, ]
[3, 0, 2, 5, -5, -1, -10, -8, -5, -9, ]
[3, -2, 3, -8, -3, 7, -10, 0, -6, -2, ]
[6, 3, -8, -8, 3, 8, -6, 9, -2, -9, ]]

[[5, 8, -8, 7, -8, -9, 6, 8, -5, 4, ]
[5, 1, -3, -4, 6, -4, 9, 9, 7, -5, ]
[2, -5, -10, -10, -8, -7, -3, -4, 3, 2, ]
[3, 0, 2, 5, -5, -1, -10, -8, -5, -9, ]
[3, -2, 3, -8, -3, 7, -10, 0, -6, -2, ]
[6, 3, -8, -8, 3, 8, -6, 9, -2, -9, ]]

[CNWindson]

@dpilger26 It really works, thx a lot! Although I couldn't understand the reason you said , it really helps a lot!