closest

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closest#

Index in array which entry is closest to a given number.

This module was written by Matthias Cuntz while at Department of Computational Hydrosystems, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany, and continued while at Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Nancy, France.

copyright:

Copyright 2012-2023 Matthias Cuntz, see AUTHORS.rst for details.

license:

MIT License, see LICENSE for details.

The following functions are provided:

closest(arr, num[, value])

Index in array which entry is closest to a given number.
History

  • Written Jan 2012 by Matthias Cuntz (mc (at) macu (dot) de)

  • Ported to Python 3, Feb 2013, Matthias Cuntz

  • Make numpy docstring format, Apr 2020, Matthias Cuntz

  • Ported into pyjams, Oct 2021, Matthias Cuntz

  • More consistent docstrings, Jan 2022, Matthias Cuntz

  • Support pandas Series and DataFrame, Jun 2023, Matthias Cuntz

closest(arr, num, value=False)[source]#

Index in array which entry is closest to a given number.

Closest returns the index of an array (arr) at which the entry is closest to a given number (num), which is argmin(abs(arr-num)).

Parameters:

  • arr (array_like) – Array to search closest entry

  • num (number) – Number to which the closest entry is searched for in arr

  • value (bool, optional) – Returns closest array element instead of index if True (default: False)

Returns:

index – Index of element closest to given number in flattend array. Use np.unravel_index to get index tuple.

Return type:

int

Examples

>>> arr = np.arange(100)/99.*5.
>>> print(closest(arr, 3.125))
62
>>> out = closest(arr, 3.125, value=True)
>>> print('{:.3f}'.format(out))
3.131

>>> arr = np.arange(100).reshape((10,10))/99.*5.
>>> out = closest(arr, 3.125, value=True)
>>> print('{:.3f}'.format(out))
3.131
>>> print(closest(arr, 3.125))
62
>>> ii = np.unravel_index(closest(arr, 3.125), arr.shape)
>>> print(ii)
(6, 2)
>>> out = arr[ii]
>>> print('{:.3f}'.format(out))
3.131
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