Indexing routines — NumPy v2.5.dev0 Manual (original) (raw)
Generating index arrays#
| c_ | Translates slice objects to concatenation along the second axis. |
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| 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, sparse]) | Return an array representing the indices of a grid. |
| ix_(*args) | Construct an open mesh from multiple sequences. |
| ogrid | An 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, shape[, 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. |
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| 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 list 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. |
Inserting data into arrays#
| place(arr, mask, vals) | Change elements of an array based on conditional and input values. |
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| 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(op[, flags, op_flags, op_dtypes, ...]) | Efficient multi-dimensional iterator object to iterate over arrays. |
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| ndenumerate(arr) | Multidimensional index iterator. |
| ndindex(*shape) | An N-dimensional iterator object to index arrays. |
| nested_iters(op, axes[, flags, op_flags, ...]) | Create nditers for use in nested loops |
| flatiter() | Flat iterator object to iterate over arrays. |
| iterable(y) | Check whether or not an object can be iterated over. |