What is the string API commonly used in JavaScript
In this issue, the editor will bring you about the string API commonly used in JavaScript. The article is rich in content and analyzes and narrates it from a professional point of view. I hope you can get something after reading this article.
The string API commonly used in JavaScript
Length:
Gets the length of the string
Var str= "abcde"
Console.log (str.length); / / 5
CharAt ():
Returns the character of the specified position
Var str= "abcde"
Console.log (str.charAt (0)); / / a
Console.log (str.charAt (3)) / / d
CharCodeAt ():
Returns the Unicode encoding of the characters at the specified position
Var str= "abcde"
Console.log (str.charCodeAt (0)); / / 97
Concat ():
Concatenate two or more strings
Var str= "abcde"
Console.log (str.concat ("ffff")); / / abcdeffff
IndexOf ():
Find the subscript corresponding to a string, and return-1 if it cannot be found
Var str= "abcde"
Console.log (str.indexOf ('c')); / / 2
Console.log (str.indexOf ('g')); / /-1
LastIndexOf ():
Check the last subscript of a string, and return-1 if it cannot be found
Var str= "abcde"
Console.log (str.lastIndexOf ('b')); / / 1
Console.log (str.lastIndexOf ('r')); / /-1
Slice (start,end):
Intercept the string, the subscript at the beginning of start and the subscript at the end of end, without the end itself; if end is null, the subscript is intercepted to the end
Var str= "abcde"
Console.log (str.slice (0Pol 3)); / / abc
Substr (start,count):
Intercept string, subscript starting with start, length intercepted by count. If count is null, the last truncation is obtained. If start is negative, it is reciprocal.
Var str= "abcde"
Console.log (str.substr (0jue 2)); / / ab
Console.log (str.substr (- 2)); / / de
Substring (start,end):
Intercept the string, the subscript of the beginning of start, the subscript of the end of end, does not contain the end itself. If the end is empty, it is intercepted to the end. If the subscript is negative, it is automatically converted to 0.
Var str= "abcde"
Console.log (str.substring (0Pol 3)); / / abc
Console.log (str.substring (- 3)); / / abcde
Split ():
Divide the string into an array of strings which is a good http://m.zykdtj.com/ for Zhengzhou expelling birthmark hospital
Var str= "abcde"
Console.log (str.split (')); / / ["a", "b", "c", "d", "e"]
Console.log (str.split (',')) / / ["abcde"]
Trim ():
Delete all spaces in the prefix and suffix of the string and save the result in a new string to return
Var str= "abcde"
Console.log (str.trim ()); / / abcde
ToLowerCase (), toUpperCase ():
Convert a string to lowercase, uppercase, and save it in a new string to return
Var str= "abCDe"
Console.log (str.toLowerCase ()); / / abcde
Console.log (str.toUpperCase ()); / / ABCDE
The difference between join () and split ()
Join splices an array into a string and returns it, with the parameters received by join as the separator between elements (default is ",")
Split takes a string as the split point with the received parameter
Var arr= ["a", "b", "c", "d", "e", "f"]
Var str= "a.b.c.d.e.f"
Console.log (arr.join ('.')); / / a.b.c.d.e.f
Console.log (str.split ('.)); / / ["a", "b", "c", "d", "e"
This is what the string API commonly used in JavaScript is like. If you happen to have similar doubts, you might as well refer to the above analysis to understand. If you want to know more about it, you are welcome to follow the industry information channel.
