wink-helpers
v2.0.0
Published
Functions for cross validation, shuffle, cartesian product and more
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wink-helpers
Functions for cross validation, shuffle, cartesian product and more
Perform cross validation for machine learning, shuffle an array randomly, remove diacritical marks from text, find cartesian product and more using wink-helpers
.
Installation
Use npm to install:
npm install wink-helpers --save
Example
// Load wink helpers
var helpers = require( 'wink-helpers' );
/* Use array helpers */
console.log( helpers.array.isArray( [] ) );
// -> true
var ppl = [ { name: 'aiden', age: 42 }, { name: 'olivia', age: 37 } ];
console.log( ppl.sort( helpers.array.ascendingOn( 'age' ) ) );
// -> [ { "name": "olivia", "age": 37 }, { "name": "aiden", "age": 42 } ]
console.log( helpers.array.product( [ [ 9, 8 ], [ 1, 2 ] ] ) );
// -> [ [ 9, 1 ], [ 9, 2 ], [ 8, 1 ], [ 8, 2 ] ]
console.log( helpers.array.shuffle( [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ] ) );
// -> [ 3, 7, 8, 9, 6, 4, 2, 1, 10, 5 ]
// Note: output will change on every call!
/* Use object helpers */
console.log( helpers.object.isObject( {} ) );
// -> true
console.log( helpers.object.isObject( new Set() ) );
// -> false
console.log( helpers.object.table( { mobile: 33, chargers: 45, usb: 27 } ) );
// -> [ [ "mobile", 33 ], [ "chargers", 45 ], [ "usb", 27 ] ]
/* Use string helper */
console.log( helpers.string.normalize( 'Résumé' ) );
// -> 'resume'
API
The helper functions are classified into array, object, string and validate.
array
isArray( value )
Tests if argument value
is a valid JS array; returns true
if it is, otherwise returns false
.
sorting compare functions
It is a set of handy compare functions for handling a variety of array sorting needs.
| compareFunction | Description |
| --- | --- |
| ascending | Sorts elements in ascending order. |
| descending | Sorts elements in descending order. |
| ascendingOnKey | It works on array of arrays, where each element is in the [ key, value ]
format. Sorts elements in ascending order on the key
. |
| descendingOnKey | Same as above, but sorts in descending order. |
| ascendingOnValue | It works on array of arrays, where each element is in the [ key, value ]
format. Sorts elements in ascending order on the value
. |
| descendingOnValue | Same as above, but sorts in descending order. |
| ascendingOn( accessor1
[,accessor2
] ) | A higher order function that returns a compare function for the accessors — refers to a key whose value will be used to determine the sort order.Can be directly used as the compare function for sort.It works on array of arrays or objects. When both the accessors are supplied, the combination is treated as a composite key for sort. |
| descendingOn( accessor1
[,accessor2
] ) | Same as above, but sorts in descending order. |
pluck( array, key, limit )
Plucks the values specified by the key
from each element of the array
of arrays or objects, and returns the resultant array. The default value of key
is 0. The number of elements to be plucked is defined by the limit
, whose default value is array.length
.
product( array )
Returns the cartesian product of the arrays present inside the array
argument. For example, if the array
argument is [ [ 1, 2, 3 ], [ 4 ], [ 5, 6 ] ]
, then the return value will be:
[
[ 1, 4, 5 ],
[ 1, 4, 6 ],
[ 2, 4, 5 ],
[ 2, 4, 6 ],
[ 3, 4, 5 ],
[ 3, 4, 6 ]
]
shuffle( array )
Randomly shuffles the order of the elements in the input array using algorithm described in Chapter 3 on Random Numbers of "The Art of Computer Programming Volume II" by Donald E Knuth.
object
isObject( value )
Tests if argument value
is a JS object; returns true
if it is, otherwise returns false
.
keys( obj )
Returns keys of the obj
in an array
.
size( obj )
Returns the number of keys in the obj
.
values( obj )
Returns all the values from each key: value
pair in the obj
in form of an array.
valueFreq( obj )
Returns the frequency or count of every unique value from each key: value
pair in the obj
in form of an object.
table( obj [, f] )
Converts each key: value
pair in the obj
into an array of [ key, value ]
pairs. Note the returned value be an array of array. Second argument - f
is optional; it is a function, which is called with each value.
string
normalize( str )
Normalizes the str
by converting it to lower case and stripping the diacritical marks (if any).
validate
isArray( value )
Alias for array.isArray()
.
isObject( value )
Alias for object.isObject()
.
isFiniteInteger( value )
Tests if argument value
is a finite integer; returns true
if it is, otherwise returns false
.
isFiniteNumber( value )
Tests if argument value
is a finite number; returns true
if it is, otherwise returns false
.
cross( classLabels )
Performs cross validation and generates detailed performance metrics along with the confusion matrix. It is a higher order function that returns an object containing evaluate()
, metrics()
, and reset()
functions. The classLabels
should be an array containing all the class labels that may be predicted.
The evaluate()
function accepts two parameters viz. truth
— the actual label and guess
— the predicted label. It is typically called for every row of validation dataset. The evaluation may fail if truth
or guess
value is not a valid classLabels
; or if guess is equal to unknown
.
The metrics()
returns an object containing macro-averaged avgPrecision
, avgRecall
, avgFMeasure
values along with other details such as label-wise recall/precision/f-measure values and the confusion matrix. A value of null
is returned if no evaluate() has been called before.
The reset()
re-initializes the current instance for another round of evaluation; the class labels defined at instance creation time are not touched.
Need Help?
If you spot a bug and the same has not yet been reported, raise a new issue or consider fixing it and sending a pull request.
About wink
Wink is a family of open source packages for Statistical Analysis, Natural Language Processing and Machine Learning in NodeJS. The code is thoroughly documented for easy human comprehension and has a test coverage of ~100% for reliability to build production grade solutions.
Copyright & License
wink-helpers is copyright 2017-18 GRAYPE Systems Private Limited.
It is licensed under the terms of the MIT License.