Javascript Python

Python-style list slicing in JavaScript

PyJsArray

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Do you love Python list slicing?

Want to do this..

items = ["apple", "ball", "cat"]

items[-1:] # returns ["cat]

items[-1] # returns "cat"

items[:1] # returns ["apple"]

Then this module is for you!

Usage

Create an array:

const array = [
    "apple",
    "ball",
    "cat",
    "dog"
];

Create a PyJsArray object, passing your array in:

const newArray = new PyJsArray(array);

Accessing from the end backwards:

newArray[-1] // returns "dog"

PyJsArray also accepts the start:end format, which must be quoted or JS will think it's an object

newArray["-2:"] // returns ["cat", "dog"]

Stepped slicing

Stepped slicing. A third "step" parameter can be passed in to return every 2nd, 3rd or nth item. It also works in reverse.

const array = [
    "apple",
    "ball",
    "cat",
    "dog",
    "elephant",
    "fish"
];

newArray["1:5:2"] // returns ["ball", "dog" ]

When reversing, start index must be higher than end index.

newArray["5:1:-2"]

• END INDEXES ARE NON-INCLUSIVE. *

In the above example, we do not get "fish" returned because "fish" is at index[5] and as 5 is our end index (non-inclusive), it gets ommitted.

That's how it works in Python.

Javascript uses : so when you want to use : QUOTE IT! sorry.