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Editorial Team
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Asked: 2026-06-19T01:39:32+00:00

I use match to split a mathematics expression into separated strings and save them

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I use match to split a mathematics expression into separated strings and save them in an array.

var STRING = ST.match(/\d*\.\d+|\d+|[()/*+-]/g);

but this method separate everything including negative numbers which are inside parentheses.
For example (-2+4) does not give me -2, instead it saves – in one index of STRING array and 2 in the next index.
Is there anyway use match and save negative numbers which are in the parentheses?

This is what I want:
(-2+4): 

STRING[0] give me (
STRING[1] give me -2
STRING[2] give me +
STRING[3] give me 4
STRING[4] give me )

and if there is no negative number work as normal:
(2+4):

STRING[0] give me (
STRING[1] give me 2
STRING[2] give me +
STRING[3] give me 4
STRING[4] give me )
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1 Answer

  1. Editorial Team

    I don’t think it’s possible to parse complex cases like "(-2+4*-(3.5--8))" with just a regex especially given we don’t have negative look behind in javascript.

    A solution would be to postprocess your match array by merging signs when they’re between a separator and an unsigned expression.

    In my opinion a regex is useful here, but only for the primary tokenization. Most of the work will be ahead of you as you’ll build the binary expression tree (or any other formal representation you choose).

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