One: array to string (3 methods)
toString(), toLocaleString(), join(), join(',')
JS allows conversion between arrays and strings. Among them, the Array method object defines 3 methods, as follows
Array method description
toString() converts an array into a string toLocaleString() converts an array into a
string of local conventions join () joins elements of an array to build a string Elements are placed into a string Elements are separated by the specified delimiter
Delimiter specified by join() Description
join() can be interpreted as a string directly, and the default comma separates
join(' ') empty connection
join(',') or join('-') or join('.') The comma in the middle is added manually, and it can also be changed to something else such as,. ! - etc.
// join()
let a= ["00", "01", "02", "03", "04"]
let b= a.join()
console.log(b)
/ / 00,01,02,03,04
console. log( typeof b)
// string
或者
// join('')
let a= ["00", "01", "02", "03", "04"]
let b= a.join('')
console.log(b)
// 0001020304
console.log( typeof b)
// string
或者
// join(',')
let a= ["00", "01", "02", "03", "04"]
let b= a.join(',')
console.log(b)
// 00,01,02,03,04
或者
// join('-')
let a= ["00", "01", "02", "03", "04"]
let b= a.join('-')
console.log(b)
// 00-01-02-03-04
或者
// join('！')
let a= ["00", "01", "02", "03", "04"]
let b= a.join('!')
console.log(b)
// 00!01!02!03!04
2. The toString() method can convert a logical value into a string and return the result
let a= ["00", "01", "02", "03", "04"]
let c = a.toString( ); //Convert the array to a string
console.log(c)
// 00,01,02,03,04
console.log(typeof c); //Return string string, indicating that it is a string type
toString() The method cannot specify the delimiter, but we can specify the replacement through the replace() method
let a= ["00", "01", "02", "03", "04"]
let f = a.toString().replace(/,/gi,'-')
console.log(f)
//Print result: 00-01-02-03-04
3. toLocaleString()
converts the array into a locally agreed string
let a= ["00", "01", "02", "03", "04"]
let e = a.toLocaleString();
console.log(e)
//Print results: 00,01,02, 03,04
2: Convert string to array (2 methods)
String method Description
split() method converts a string into an array
Spread operator (…) The spread operator
1 in es6, the split() method is used to convert Splitting a string into a string array
is also used to split a string into a string array, what is the difference between split(','), split(), and split(' ')?
split() method description
split(',') Each character is separated by a comma
split() can be understood as a string directly, the default comma is separated
split(' ') Empty string Each character will be split
let arr = 'aa,bb,cc,dd'
let newStr = arr.split(',')
console.log(newStr)
// ["aa", "bb", "cc", "dd"]
let arr = 'aa,bb,cc,dd'
let newStr = arr.split()
console.log(newStr)
// ["aa,bb,cc,dd"]
if an empty string ("") is used as separator, then each character in stringObject will be divided
let arr = 'aa,bb,cc,dd'
let newStr = arr.split('')
console.log(newStr)
// ["a", "a", ",", "b", "b" , ",", "c", "c", ",", "d", "d"]
2. The expansion operator in es6
let arr = 'aa,bb,cc,dd'
let newStr = [. ..arr]
console.log(newStr)
// ["a", "a", ",", "b", "b", ",", "c", "c", ",", " d", "d"]