Because the concat method is less efficient than the + operator, it is recommended to use the latter instead. concat.js let a = 'old'; let c = a.concat(' tree'); console.log(c); The example concatenates two strings with the built-in concat method. ...
普通写法：我们通常使用Array中的concat()方法合并两个数组。用concat()方法来合并两个或多个数组，不会更改现有的数组，而是返回一个新的数组。请看一个简单的例子：let apples = ['', ''];let fruits = ['', '', ''].concat(apples);console.log( fruits );//=> ["", "", "", "", ""]简...
console.log("".concat(null)); // null console.log("".concat(true)); // true console.log("".concat(4, 5)); // 45 let str1 = "Hello"; let str2 = "World"; // concatenating two strings let newStr = str1.concat(", ", str2, "!"); console.log(newStr); // Hello, ...
x >= y // => false: greater-than or equal "two" === "three" // => false: the two strings are different "two" > "three" // => true: "tw" is alphabetically greater than "th" false === (x > y) // => true: false is equal to false // Logical operators combine or inv...
concat() Joins two or more strings. replace() Replace a string with another string. split() Converts the string to an array of strings. substr() Returns a part of a string by taking the starting position and length of the substring. substring() Returns a part of the string from the ...
concat()Returns two or more joined strings constructorReturns the string's constructor function endsWith()Returns if a string ends with a specified value fromCharCode()Returns Unicode values as characters includes()Returns if a string contains a specified value ...
我们通常使用Array中的concat()方法合并两个数组。用concat()方法来合并两个或多个数组,不会更改现有的数组,而是返回一个新的数组。请看一个简单的例子: let apples = [' ', ' ']; let fruits = [' ', ' ', ' '].concat(apples); console.log( fruits ); ...
JavaScript String concat() concat()joins two or more strings: Example lettext1 ="Hello"; lettext2 ="World"; lettext3 = text1.concat(" ", text2); Try it Yourself » Theconcat()method can be used instead of the plus operator. These two lines do the same: ...
that concatenates two strings. This is overly restrictive, though, since other types support concatenation (Array a, for example). One could use a type variable to define a polymorphic "concat" function:// _concat :: a -> a -> a const _concat = def ('_concat') ({}) ([a, a, a...
reduce( (acc, cur) => { return acc.concat(cur); }, [1, 2], );A: [0, 1, 2, 3, 1, 2] B: [6, 1, 2] C: [1, 2, 0, 1, 2, 3] D: [1, 2, 6]Answer Answer: C [1, 2] is our initial value. This is the value we start with, and the value of the very ...