常用API

参见

Indexing

Generating index arrays

c_ Translates slice objects to concatenation along the second axis.
r_ Translates slice objects to concatenation along the first axis.
s_ A nicer way to build up index tuples for arrays.
nonzero(a) Return the indices of the elements that are non-zero.
where(condition, [x, y]) Return elements chosen from x or y depending on condition.
indices(dimensions[, dtype]) Return an array representing the indices of a grid.
ix_(*args) Construct an open mesh from multiple sequences.
ogrid nd_grid instance which returns an open multi-dimensional “meshgrid”.
ravel_multi_index(multi_index, dims[, mode, …]) Converts a tuple of index arrays into an array of flat indices, applying boundary modes to the multi-index.
unravel_index(indices, dims[, order]) Converts a flat index or array of flat indices into a tuple of coordinate arrays.
diag_indices(n[, ndim]) Return the indices to access the main diagonal of an array.
diag_indices_from(arr) Return the indices to access the main diagonal of an n-dimensional array.
mask_indices(n, mask_func[, k]) Return the indices to access (n, n) arrays, given a masking function.
tril_indices(n[, k, m]) Return the indices for the lower-triangle of an (n, m) array.
tril_indices_from(arr[, k]) Return the indices for the lower-triangle of arr.
triu_indices(n[, k, m]) Return the indices for the upper-triangle of an (n, m) array.
triu_indices_from(arr[, k]) Return the indices for the upper-triangle of arr.

Indexing-like operations

take(a, indices[, axis, out, mode]) Take elements from an array along an axis.
take_along_axis(arr, indices, axis) Take values from the input array by matching 1d index and data slices.
choose(a, choices[, out, mode]) Construct an array from an index array and a set of arrays to choose from.
compress(condition, a[, axis, out]) Return selected slices of an array along given axis.
diag(v[, k]) Extract a diagonal or construct a diagonal array.
diagonal(a[, offset, axis1, axis2]) Return specified diagonals.
select(condlist, choicelist[, default]) Return an array drawn from elements in choicelist, depending on conditions.
lib.stride_tricks.as_strided(x[, shape, …]) Create a view into the array with the given shape and strides.

Inserting data into arrays

place(arr, mask, vals) Change elements of an array based on conditional and input values.
put(a, ind, v[, mode]) Replaces specified elements of an array with given values.
put_along_axis(arr, indices, values, axis) Put values into the destination array by matching 1d index and data slices.
putmask(a, mask, values) Changes elements of an array based on conditional and input values.
fill_diagonal(a, val[, wrap]) Fill the main diagonal of the given array of any dimensionality.

Iterating over arrays

nditer Efficient multi-dimensional iterator object to iterate over arrays.
ndenumerate(arr) Multidimensional index iterator.
ndindex(*shape) An N-dimensional iterator object to index arrays.
nested_iters Create nditers for use in nested loops
flatiter Flat iterator object to iterate over arrays.
lib.Arrayterator(var[, buf_size]) Buffered iterator for big arrays.