java string. trim of function in the role of examples and source code

trim() removes whitespace from the beginning and end of a string.

public static void main(String arg[]){
	String a=" hello world ";
	String b="hello world";
	System.out.println(b.equals(a));
	a=a.trim();
	// Remove Spaces at the beginning and end of the string  
	System.out.println(a.equals(b));
}

Execution Results:

a: hello world ,false
a:hello world,true

trim () source code:

public String trim() {
 int arg0 = this.value.length;
 // Gets the length of this string 
 int arg1 = 0;
 　　　　　　　  // The statement 1 a int  Value and assign a value of 0
 char[] arg2;
 　　　　　　　　 // The statement 1 a char An array of 
 for (arg2 = this.value; arg1 < arg0 && arg2[arg1] <= 32; ++arg1) {
  　　 // Assigns this character array to arg2 Character array ( java The bottom of the string is an array of characters, and this array of characters is String Of the class value Attribute); 
  　　 // Why less than or equal to 32, Please see ASCII Clock, ASCII table 32 said 1 A space, 32 The following are tab Tabs, \n Line breaks, \r A carriage return, \b Backspace, etc. 
  　　 // if 1 The string is"  123  ", so this method is completed, arg1 Will be assigned a value of 1.
  ;
 }
 while (arg1 < arg0 && arg2[arg0 - 1] <= 32) {
  --arg0;
  　　 // if 1 The string is"  123  ", so this method is completed, arg0 Will be assigned a value of 4
 }
 return arg1 <= 0 && arg0 >= this.value.length ? this : this.substring(arg1, arg0);
 　　  //arg1==1, So walk behind. this.substring(1,4)
 　　  // With head and without tail, the result is" 123 " 
}

conclusion

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