How to determine whether a certain value exists in an array in jquery

During the development process, we often need to determine whether a specific value exists in an array. For such needs, jQuery provides a very convenient method called $.inArray().

$.inArray() method accepts two parameters: the value to find and the array to search. If the value you are looking for exists in the array, the method returns its index in the array (starting from 0), otherwise it returns -1.

The following is a code example using the $.inArray() method:

var arr = [1, 2, 3, 4, 5];
var num = 3;
if ($.inArray(num, arr) !== -1) {
    console.log("数组中存在3");
} else {
    console.log("数组中不存在3");
}

In the above example code, we define an array arr with a length of 5, and a value to be found num. When the return value of the $.inArray() method is not equal to -1, it means that the value exists in the array, so "3 exists in the array" is printed. If the num value is 6, what is printed is "6 does not exist in the array".

$.inArray() method can also be used in string arrays, Boolean arrays and object arrays. The same syntax applies to all types of arrays.

In addition to the $.inArray() method, jQuery also provides a method $.isArray() to determine whether the variable is an array type. This method accepts a parameter and returns true if the parameter is an array type, otherwise it returns false.

The following is a code example using the $.isArray() method:

var arr = [1, 2, 3, 4, 5];
if ($.isArray(arr)) {
    console.log("arr是一个数组");
} else {
    console.log("arr不是一个数组");
}

In the above example code, we determine whether the variable arr is an array type, because its type is indeed an array, So it prints "arr is an array".

In general, $.inArray() and $.isArray() are very practical array methods in jQuery, which can help us complete array operations conveniently and quickly.

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