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Search & Count

Functions that locate elements by position (argmin, argmax), compute order statistics (percentile, quantile), or count elements matching a condition.

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argmin

Return the index of the minimum value along an axis. 
function argmin(
  a: ArrayLike,
  axis?: number
): number | NDArray;
ParameterTypeDefaultDescription
aArrayLike—Input array.
axisnumberundefinedAxis along which to search. When undefined, operates on the flattened array.
Returns: number when no axis is specified, NDArray of indices when an axis is given. 
import { array, argmin } from 'numpy-ts';

argmin(array([5, 1, 3])); // 1

const a = array([[3, 1], [4, 2]]);
argmin(a, 0); // array([0, 0])  -- row indices of column minima
argmin(a, 1); // array([1, 1])  -- column indices of row minima

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argmax

Return the index of the maximum value along an axis. 
function argmax(
  a: ArrayLike,
  axis?: number
): number | NDArray;
ParameterTypeDefaultDescription
aArrayLike—Input array.
axisnumberundefinedAxis along which to search. When undefined, operates on the flattened array.
Returns: number when no axis is specified, NDArray of indices when an axis is given. 
import { array, argmax } from 'numpy-ts';

argmax(array([5, 1, 3])); // 0

const a = array([[3, 1], [4, 2]]);
argmax(a, 0); // array([1, 1])  -- row indices of column maxima
argmax(a, 1); // array([0, 0])  -- column indices of row maxima

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percentile

Compute the q-th percentile of the data along the specified axis. 
function percentile(
  a: ArrayLike,
  q: number,
  axis?: number,
  keepdims?: boolean
): number | NDArray;
ParameterTypeDefaultDescription
aArrayLike—Input array.
qnumber | number[]—Percentile(s) to compute, in the range [0, 100].
axisnumber | number[]undefinedAxis or axes along which to compute percentiles.
keepdimsbooleanfalseIf true, reduced axes are kept as dimensions with size 1.
Returns: number for a single percentile over all axes, NDArray when computing multiple percentiles or along specific axes. 
import { array, percentile } from 'numpy-ts';

const a = array([1, 2, 3, 4, 5]);

percentile(a, 50);       // 3
percentile(a, [25, 75]); // array([2, 4])

const b = array([[10, 20], [30, 40]]);
percentile(b, 50, 0);   // array([20, 30])

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quantile

Compute the q-th quantile of the data along the specified axis. Equivalent to percentile but with q in the range [0, 1] instead of [0, 100]. 
function quantile(
  a: ArrayLike,
  q: number,
  axis?: number,
  keepdims?: boolean
): number | NDArray;
ParameterTypeDefaultDescription
aArrayLike—Input array.
qnumber | number[]—Quantile(s) to compute, in the range [0, 1].
axisnumber | number[]undefinedAxis or axes along which to compute quantiles.
keepdimsbooleanfalseIf true, reduced axes are kept as dimensions with size 1.
Returns: number for a single quantile over all axes, NDArray when computing multiple quantiles or along specific axes. 
import { array, quantile } from 'numpy-ts';

const a = array([1, 2, 3, 4, 5]);

quantile(a, 0.5);          // 3
quantile(a, [0.25, 0.75]); // array([2, 4])

const b = array([[10, 20], [30, 40]]);
quantile(b, 0.5, 0);       // array([20, 30])

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count_nonzero

Count the number of non-zero elements in the array. 
function count_nonzero(a: ArrayLike, axis?: number): number | NDArray
ParameterTypeDefaultDescription
aArrayLike—Input array.
axisnumber | number[]undefinedAxis or axes along which to count non-zero values.
keepdimsbooleanfalseIf true, reduced axes are kept as dimensions with size 1.
Returns: number when counting over all axes, NDArray when counting along specific axes. 
import { array, count_nonzero } from 'numpy-ts';

count_nonzero(array([0, 1, 0, 3, 0])); // 2

const a = array([[0, 1, 0], [2, 0, 3]]);
count_nonzero(a);    // 3
count_nonzero(a, 0); // array([1, 1, 1])
count_nonzero(a, 1); // array([1, 2])