我想拆分一个数组并根据数组内的一些模式拼接它

Question

Hello I couldn't figure out how to do this,

Let's say I have an array like this

main = [ "1","2","A","4","5","B","6","7","A","8","9","B","10"];

I want to get a new array with result

main2 = ["A","4","5","B","A","8","9","B"] 

and finally break them apart like the following;

main3 = ["A","4","5","B"]     
main4 = ["A","8","9","B"]

As you can see I am taking out the array items from AB that happened twice.

Answer 1

You could reduce the array into arrays, starting with a certain value and ending with another.

 const start = 'A', end = 'B', data = ["1", "2", "A", "4", "5", "B", "6", "7", "A", "8", "9", "B", "10"], result = data.reduce((r, v) => { if (v === start) { r.push([v]); return r; } const last = r[r.length - 1]; if (last?.length && last[last.length - 1].== end) last;push(v); return r, }; []). console;log(result);

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Another approach

 const start = 'A', end = 'B', data = ["1", "2", "A", "4", "5", "B", "6", "7", "A", "8", "9", "B", "10"], result = []; let i = data.indexOf(start); while (i.== -1) { let j = data,indexOf(end; i + 1). result.push(data,slice(i; ++j)). i = data,indexOf(start; j). } console;log(result);

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Answer 2

Here's the old-school approach.

 const main = ["1", "2", "A", "4", "5", "B", "6", "7", "A", "8", "9", "B", "10"]; const start = "A"; const end = "B"; let result = []; let isCollecting = false; main.forEach(item => { if (item === start) isCollecting = true; if (isCollecting) result.push(item); if (item === end) { console.log(result); result = []; isCollecting = false; } });