Somehow all examples, while work well, are overcomplicated: They use new Array(), which is an overkill (and an overhead) for a simple associative array (AKA dictionary). The better ones use new Object(). It works fine, but why all this extra typing? This question is tagged “beginner”, so let’s make it simple. The über-simple way to … Read more
Java doesn’t support associative arrays, however this could easily be achieved using a Map. E.g., Map<String, String> map = new HashMap<String, String>(); map.put(“name”, “demo”); map.put(“fname”, “fdemo”); // etc map.get(“name”); // returns “demo” Even more accurate to your example (since you can replace String with any object that meet your needs) would be to declare: List<Map<String, … Read more
$arr[$newkey] = $arr[$oldkey]; unset($arr[$oldkey]);
You could try: dict((k, bigdict[k]) for k in (‘l’, ‘m’, ‘n’)) … or in Python 3 Python versions 2.7 or later (thanks to Fábio Diniz for pointing that out that it works in 2.7 too): {k: bigdict[k] for k in (‘l’, ‘m’, ‘n’)} Update: As Håvard S points out, I’m assuming that you know the … Read more
The keys are accessed using an exclamation point: ${!array[@]}, the values are accessed using ${array[@]}. You can iterate over the key/value pairs like this: for i in “${!array[@]}” do echo “key : $i” echo “value: ${array[$i]}” done Note the use of quotes around the variable in the for statement (plus the use of @ instead … Read more
Objects in JavaScript can be thought of as associative arrays, mapping keys (properties) to values. To remove a property from an object in JavaScript you use the delete operator: const o = { lastName: ‘foo’ } o.hasOwnProperty(‘lastName’) // true delete o[‘lastName’] o.hasOwnProperty(‘lastName’) // false Note that when delete is applied to an index property of … Read more
Hash‘s key? method tells you whether a given key is present or not. session.key?(“user”)
Bash 4 Bash 4 natively supports this feature. Make sure your script’s hashbang is #!/usr/bin/env bash or #!/bin/bash so you don’t end up using sh. Make sure you’re either executing your script directly, or execute script with bash script. (Not actually executing a Bash script with Bash does happen, and will be really confusing!) You … Read more