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gjoinBetween

Return a string by joining strided array elements using a specified separator for each pair of consecutive elements.

Usage

var gjoinBetween = require( '@stdlib/blas/ext/base/gjoin-between' );

gjoinBetween( N, prefix, suffix, x, strideX, separators, strideS )

Returns a string by joining strided array elements using a specified separator for each pair of consecutive elements.

var x = [ 1, 2, 3, 4 ];
var sep = [ ' + ', ' - ', ' != ' ];

var str = gjoinBetween( x.length, 'op: ', '', x, 1, sep, 1 );
// returns 'op: 1 + 2 - 3 != 4'

The function has the following parameters:

  • N: number of indexed elements.
  • prefix: string to prepend to the output string.
  • suffix: string to append to the output string.
  • x: input array.
  • strideX: stride length for x.
  • separators: separators array.
  • strideS: stride length for separators.

The N and stride parameters determine which elements in the strided arrays are accessed at runtime. For example, to join every other element:

var x = [ 1, 2, 3, 4, 5, 6 ];
var sep = [ ',', '-' ];

var str = gjoinBetween( 3, '', '', x, 2, sep, 1 );
// returns '1,3-5'

Note that indexing is relative to the first index. To introduce an offset, use typed array views.

var Float64Array = require( '@stdlib/array/float64' );

// Initial array:
var x0 = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );

// Create an offset view:
var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

// Join elements:
var sep = [ ' | ', ' | ' ];
var str = gjoinBetween( 3, '[', ']', x1, 2, sep, 1 );
// returns '[2 | 4 | 6]'

gjoinBetween.ndarray( N, prefix, suffix, x, strideX, offsetX, separators, strideS, offsetS )

Returns a string by joining strided array elements using a specified separator for each pair of consecutive elements and alternative indexing semantics.

var x = [ 1, 2, 3, 4 ];
var sep = [ ' + ', ' - ', ' != ' ];

var str = gjoinBetween.ndarray( x.length, 'op: ', '', x, 1, 0, sep, 1, 0 );
// returns 'op: 1 + 2 - 3 != 4'

The function has the following additional parameters:

  • offsetX: starting index for x.
  • offsetS: starting index for separators.

While typed array views mandate a view offset based on the underlying buffer, the offset parameters support indexing semantics based on starting indices. For example, to access only the last three elements of the strided array:

var x = [ 1, 2, 3, 4, 5, 6 ];
var sep = [ ' | ', ' | ' ];

var str = gjoinBetween.ndarray( 3, '[ ', ' ]', x, 1, x.length-3, sep, 1, 0 );
// returns '[ 4 | 5 | 6 ]'

Notes

  • If N <= 0, both functions return the prefix and suffix joined together.
  • The separators array is assumed to have at least N-1 indexed elements (i.e., equal to the number of "gaps" between consecutive elements).
  • If an array element is either null or undefined, both functions serialize the element as an empty string.
  • Both functions support array-like objects having getter and setter accessors for array element access (e.g., @stdlib/array/base/accessor).

Examples

var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
var filled = require( '@stdlib/array/base/filled' );
var gjoinBetween = require( '@stdlib/blas/ext/base/gjoin-between' );

var x = discreteUniform( 10, -100, 100, {
    'dtype': 'generic'
});
console.log( x );

var sep = filled( ' | ', x.length - 1 );
var out = gjoinBetween( x.length, '[ ', ' ]', x, 1, sep, 1 );
console.log( out );