Method Summary of array and string in JavaScript _ basics

A summary of the method of array

Will change the original array

Push, Unshift method, return length. Added is worth the return length, the other returns that element

Pop,shift returns the element

Reverse returns the element

Splice (Start,deletecount,additem ...), removed and added from the original array, returns the deleted array

Will not change the original array, return the new array

Concat,join,slice (Start,end)

Remember that these 3 are returned to the new array, others will change the original array

Ii. Summary of the methods of sting

Does not change the original value, it returns a new string or other value.

1, it is necessary to remember that String.match (RegExp without G) and regexp.exec (string) the same result.

If you are grouping with captures, subscript 0 matched substrings, subscript 1 grouped 1 captured text

If marked with G, String generates an array that contains all the matches (except for the capture groupings); The regular exec, which can be judged by step down, is not null.

Reg has all the lastindex.

2, String.slice (start,end), the end parameter is equal to the last character you want to take position +1, if you want to start from position p of the nth characters, use String.slice (p,p+n)

String.substring and Array.slice methods.

3, for the replacement or grouping can be used regular

String.Split (separator,limit), limit can limit the number of fragments to be divided, just as there is no G

String.Replace (Searcdhvalue,replacevalue), searcdhvalue with G, replaces all matches, and if not, replaces only the first match.

If it is a string, the value is replaced at the first occurrence

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