Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/axil/ndfind
https://github.com/axil/ndfind
Last synced: 12 days ago
JSON representation
- Host: GitHub
- URL: https://github.com/axil/ndfind
- Owner: axil
- Created: 2023-04-28T07:14:10.000Z (over 1 year ago)
- Default Branch: master
- Last Pushed: 2023-05-11T21:25:07.000Z (over 1 year ago)
- Last Synced: 2024-11-15T02:29:15.756Z (about 1 month ago)
- Language: Cython
- Size: 1.15 MB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# ndfind
[](https://pypi.python.org/pypi/ndfind)
[](https://pypi.org/project/ndfind/)
[](https://github.com/psf/black)
[](https://pypi.org/project/ndfind/)
A collection of three cython-optimized search functions for NumPy. When the required value is found,
they return immediately, without scanning the whole array. It can result in 1000x or larger speedups for
huge arrays if the value is located close to the the beginning of the array. It is at least as fast as
`np.where()` if the value is close to the end of the array.
- `find(a, v)` finds v in a, returns index of the first match or -1 if not found
- `first_above(a, v)` finds first element in a that is strictly greater than `v`,
returns its index or -1 if not found
- `first_nonzero(a)` finds the first nonzero element in a,
returns its index or -1 if not found
## Installation:
pip install ndfind
Writen in Cython. Binary wheels built for Python 3.8-3.11 on Windows, Linux, and Mac OS.
## Documentation
- `find(a, v, rtol=1e-05, atol=1e-08, sorted=False, missing=-1, raises=False)`
Returns the index of the first element in `a` equal to `v`.
If either a or v (or both) is of floating type, the parameters
`atol` (absolute tolerance) and `rtol` (relative tolerance)
are used for comparison (see `np.isclose()` for details).
For 1D returns the index as an integer scalar; for 2D and above, returns a tuple of indices.
In 2D and above the the values in `a` are always tested and returned in
row-major, C-style order.
If `v` is not in `a`, returns the `missing` value (-1 by default)
or raises a `ValueError` if `raises=True`.
For example,
```python
>>> find([3, 1, 4, 1, 5], 4)
2
>>> find([1, 2, 3], 7)
-1
>>> find([1.1, 1.2, 1.3], 1.2)
1
>>> find(np.arange(0, 1, 0.1), 0.3)
3
>>> find([[3, 8, 4], [5, 2, 7]], 7)
(1, 2)
>>> find([[3, 8, 4], [5, 2, 7]], 9)
-1
>>> find([999980., 999990., 1e6], 1e6)
1
>>> find([999980., 999990., 1e6], 1e6, rtol=1e-9)
2
```
- `first_above(a, v, sorted=False, missing=-1, raises=False)`
Returns the index of the first element in `a` strictly greater than `v`.
If either a or v (or both) is of floating type, the parameters
`atol` (absolute tolerance) and `rtol` (relative tolerance)
are used for comparison (see `np.isclose()` for details).
If there is no value in `a` greater than `v`, returns the `default` value
(-1 by default) or raises a `ValueError` if `raises=True`.
`sorted`, use binary search to speed things up (works only if the array is sorted)
`a` must be 1-dimensional.
For example,
```python
>>> first_above([4, 5, 8, 2, 7], 6)
2
>>> first_above([[4, 5, 8], [2, 7, 3]], 6)
(0, 2)
>>> first_above([5, 6, 7], 9)
3
```
- `first_nonzero(a, missing=-1, raises=False)`
Returns the index of the first nonzero element in `a`.
In 2D and above the the values in `a` are always tested and returned in
row-major, C-style order.
For example,
```python
>>> first_nonzero([0, 0, 7, 0, 5])
2
>>> first_nonzero([False, True, False, False, True])
1
>>> first_nonzero([[0, 0, 0, 0], [0, 0, 5, 3]])
(1, 2)
```
## Testing
Run `pytest` in the project root.