diff options
Diffstat (limited to 'numpy/core/fromnumeric.py')
| -rw-r--r-- | numpy/core/fromnumeric.py | 21 |
1 files changed, 14 insertions, 7 deletions
diff --git a/numpy/core/fromnumeric.py b/numpy/core/fromnumeric.py index 5b67a0dc5..373e0fde8 100644 --- a/numpy/core/fromnumeric.py +++ b/numpy/core/fromnumeric.py @@ -1615,16 +1615,16 @@ def nonzero(a): Examples -------- - >>> x = np.array([[1,0,0], [0,2,0], [1,1,0]]) + >>> x = np.array([[3, 0, 0], [0, 4, 0], [5, 6, 0]]) >>> x - array([[1, 0, 0], - [0, 2, 0], - [1, 1, 0]]) + array([[3, 0, 0], + [0, 4, 0], + [5, 6, 0]]) >>> np.nonzero(x) (array([0, 1, 2, 2]), array([0, 1, 0, 1])) >>> x[np.nonzero(x)] - array([1, 2, 1, 1]) + array([3, 4, 5, 6]) >>> np.transpose(np.nonzero(x)) array([[0, 0], [1, 1], @@ -1636,7 +1636,7 @@ def nonzero(a): boolean array and since False is interpreted as 0, np.nonzero(a > 3) yields the indices of the `a` where the condition is true. - >>> a = np.array([[1,2,3],[4,5,6],[7,8,9]]) + >>> a = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]]) >>> a > 3 array([[False, False, False], [ True, True, True], @@ -1644,7 +1644,14 @@ def nonzero(a): >>> np.nonzero(a > 3) (array([1, 1, 1, 2, 2, 2]), array([0, 1, 2, 0, 1, 2])) - The ``nonzero`` method of the boolean array can also be called. + Using this result to index `a` is equivalent to using the mask directly: + + >>> a[np.nonzero(a > 3)] + array([4, 5, 6, 7, 8, 9]) + >>> a[a > 3] # prefer this spelling + array([4, 5, 6, 7, 8, 9]) + + ``nonzero`` can also be called as a method of the array. >>> (a > 3).nonzero() (array([1, 1, 1, 2, 2, 2]), array([0, 1, 2, 0, 1, 2])) |