how to split on specific string in nodejs?

Question

I want to split string for ">" but not when >> in JavaScript.

But once I am doing a split const words = str.split('>'); it is splitting >> as well.

Currently, after the split I look for "> >" and then substitute them with ">>".

How to implement it properly.

Removed python from title, since the question talks about and is tagged javascript. — evolutionxbox
– evolutionxbox, Commented Mar 16, 2022 at 16:58
Split on a regex? str.split(/>(?!>)/g) This will still split on the second of the two >s though. — Aplet123
– Aplet123, Commented Mar 16, 2022 at 16:59
Does this help: console.log('a>b>>c>d>>e>f;'.replaceAll('>>', '^^^').split('>').map(x => x.replace('^^^', '>>'))); (NOTE: You may use a different temporary replacement-placeholder insteadof '^^^') — jsN00b
– jsN00b, Commented Mar 16, 2022 at 17:35

tmarwen · Accepted Answer · 2022-04-11 14:48:12Z

1

You can use a regular expression leveraging:

Negative lookbehind (?>!) causing a group to not be considered when the pattern matches before the main expression
Negative lookahead (?!) causing a group to not be considered when the pattern matches after the main expression

The resulting pattern would be as follows:

/(?<!>)>(?!>)/

Using the patter to tokenize an input would lead the desired results:

"here>>I>am".split(/(?<!>)>(?!>)/) // => [ 'here>>I', 'am' ]

answered Mar 16, 2022 at 17:45

tmarwen

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