Trying to match array index pattern in string using Regex

user_14966581 0
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I'm using regex to get the indices of variables accessing pattern represented as string, for example:

string = "test[2][56].var1[4]"

The regex match result in the groups 2, 56, 4 captured.

matchGroups = ["2", "56", "4"]

The regex below works.

\[([^\.\]]+)\]

But I can't allow cases like:

"test.[3].var1" or "test[3]/"

I tried to limit the characters allowed before and after each group using the regex below:

[\]a-zA-Z0-9]\[([^\.\]]+)\]([\[a-zA-Z0-9])?

But some cases stopped working like the case "test[0].var7[3][4]"(4 is not captured).

I need help to make this work with all cases again(cases are in the link below).

https://regex101.com/r/mOgOHn/2

match javascript regex string
2 Answers

I would replace the string, then do matching

Replace Regex:

/.*?\[(\d+)\].*?/

Replace the string where any number between brackets is replaced by a number followed by ,

Match Regex:

/\d+(?=,)/

Look ahead positive; which Find any number followed by ,

const captureNumber = str => str.replace(/.*?\[(\d+)\].*?/g, "$1,").match(/\d+(?=,)/g)

console.log(captureNumber("test[0].var7[3][4]")); //[ "0", "3", "4" ]
console.log(captureNumber("test[3]/")); //[ "3" ] 
console.log(captureNumber("test.[3].var1")); //[ "3" ] 
console.log(captureNumber("test[2][56].var1[4]")); //[ "2", "56", "4" ]

user_145297790

the simplest would be to use a regexp using a positive lookbehind and a positive lookahead. To this, you can add safety on spaces in case you have a case like "test[ 2 ][ 56 ].var1[ 4 ]", to which a .trim() method string must be applied. Here is a snippet illustrating this:

const getIndex = str => str.match(/(?<=\[) *\d+ *(?=\])/g).map(val => val.trim());

console.log(getIndex("test[0].var7[3][4]")); //[ "0", "3", "4" ]
console.log(getIndex("test[3]/")); //[ "3" ]
console.log(getIndex("test.[3].var1")); //[ "3" ]
console.log(getIndex("test[2 ][   56   ].var1[4 ]")); //[ "2", "56", "4" ]

Good luck !

user_169215400
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