JavaScript string objects Common API functions Summary (connection, substitution, segmentation, conversion, etc.) _javascript tips

The examples in this article describe the common API functions for JavaScript string objects. Share to everyone for your reference, specific as follows:

1. Concat (str1,str2,)

Connection string

2. IndexOf (Str,start)

Returns the position of the first occurrence of STR in a string

var str = "Hello world";
Str.indexof ("Hello"); 0
str.indexof ("O", 5);//7
Str.indexof ("World");//-1

3. LastIndexOf (Str,start)

Returns the last occurrence of str in a string

var str = "Hello world";
Str.lastindexof ("Hello"); 0
str.lastindexof ("O", 3);//-1
str.lastindexof ("O", 5);//4

4. Replace (regexp/substr,replacement)

Substitute some characters in a string for another character, or replace one with a regular match

var str = "I is Allen.";
Str.replace ("is", "AM"); "I am Allen."

5. Slice (start,end)

Returns a fragment of a string

var str = "I am Jack.";
Str.slice (3,7); "M Ja"
str.slice (3);//"M Jack."
Str.slice (3,-3); "M Ja"

6. Split (Separator,limit)

Splits a string into substrings and then returns the result as an array of strings

var str = "Hello world";
Str.split (""); ["Hello", "World"]
str.split ("", 1); ["Hello"]

7. substr (Start,lenght)

Returns a string with a specified length starting at the specified position

var str = "How do I do?"
Str.substr (4,2); "
do
" str.substr (4); Str.substr (4,0); ""
str.substr (4,-1); ""
Str.substr (-3); "Do?"

8. SUBSTRING (start,end)

Returns a string at the specified position in a string object that contains the character at start, but does not contain a character at the end

var str = "How do I do?"
Str.substring (0,3); "How"

9. toLowerCase ()

Converts a string to lowercase

toUpperCase ()

Converts a string to uppercase

var str = "How do I do?"
Str.tolowercase (); "How did you do?"
Str.touppercase (); "How did you do?"

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I hope this article will help you with JavaScript programming.