JS array splicing "suggested collection"

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js Array splicing method of

Method 1 ：concat Method splicing （ Returns a new array ）

var a1 = [1,2,3,4,5];

var a2 = [‘a’,’b’,’c’];

var newa = a1.concat(a2);

Result Type ：object

concat Method ： Used to connect two or more arrays , Generate a new array ,concat The following array is the element of the array when operating , Not an array

Method 2 ：join Method splicing （ Returns a new array ）

var a1 = [1,2,3,4,5];

var a2 = [‘a’,’b’,’c’];

var newa = a1.join()+’,’+a2.join();

Return results ：1,2,3,4,5,a,b,c

Result Type ：string

join Method ： Put all the elements of the array into a string , And then connect these strings , Insert... Between two elements separator String .separator stay join() Comma when no delimiter is added （‘,’）, stay join(‘.’) When adding a delimiter, use the provided symbol to split .

Method 3 ： combination apply perhaps call Use

var a1 = [1,2,3,4,5];

var a2 = [‘a’,’b’,’c’];

a1.push.apply(a1,a2);

Result Type ：object

apply Method ： Write methods for different objects , take a1 Of push Methods used in a1 On , receive a2( An array type ) Parameters

var a1 = [1,2,3,4,5];

var a2 = [‘a’,’b’,’c’];

a1.push.call(a1,…a2);

Result Type ：object

call Method ： A method that calls an object , Replace the current object with another object , The parameters of an object are parameter sequences

explain ：

call([thisObj[,arg1[, arg2[, [,.argN]]]]])

Parameters

1）thisObj optional . The object that will be used as the current object .

2）arg1, arg2, , argN optional . Method parameter sequence to be passed .

Method four ：es6 The extension operator of

var a1 = [1,2,3,4,5];

var a2 = [‘a’,’b’,’c’];

a1.push(…a2)

Result Type ：object

Extension operator ： like rest Inverse operation of parameter , Convert an array into a comma separated sequence of parameters , Mainly used for function calls .

Method five ： Traversal array

var a1 = [1,2,3,4,5];

var a2 = [‘a’,’b’,’c’];

a2.forEach((item) => {a1.push(item); })

Result Type ：object

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