JavaScript substring method to take slice, substr, substringcomparison table

 

  

   

in a programming language , strings can be said is the most common type , and the string in the program operation is also very frequent. When the program comes with a variety of string manipulation language method, using the programming language program when there is a lot of convenience, improve development efficiency. But when the method too much , or even similar purpose , parameters identical time, it is likely to cause confusion difficult to choose the dilemma .

   

In JavaScript there is such a situation , take the string for a substring operation , JavaScript provides three different ways : slice , substr , substring . While searching online casual look , you can find the article describes the difference between the three , but each time you use it , still confused no choice. Therefore, the difference between binding online presentation , in this paper the similarities and differences between them will be listed in the table for easy reference and distinction.

test string : "0123456789" < / span>
browsers : Chrome Version 29.0.1547.76
operating System : Mac OS X Version 10.8.5

   

        

  

 

   

  

      

  

   

  

   

  

   

  

   

  

   

  

   

  

   

  

   

  

   

  

   

  

   

  

   

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           

	parameter		method
	parameter 1	parameter 2	slice (begin [, end])	substr (start [, length])	substring (from [, to])
Parameter / Result	7		789	789	789
Description	only parameter 1 , omit parameter 2		from parameter 1 specifies the coordinates of the end of the string interception
Parameter / Result	-3		789	789	0123456789
Description	parameter 1 is negative		calculated from the end of the string position *		as 0
Parameter / Result	21
Description	parameter 1 is greater than or equal to the length of the string		as string length, that returns an empty string
Parameter / Result	"3.21"		3456789	3456789	3456789
Description	parameter 1 to float or containing only numbers string		like parseInt () converts a numeric value to an integer
Parameter / Result	NaN		0123456789	0123456789	0123456789
Description	parameter 1 non- valid value		regarded as non- valid value 0
Parameter / Result	3	7	3456	3456789	3456
Description	both parameter 1 , there parameter 2		from parameter 1 position to intercept parameter 2 position	from parameter 1 location interception length is parameter 2 characters	same slice ()
Parameter / Result	7	3		789	3456
Description	parameter 1 is greater than parameter 2		returns an empty string	from parameter 1 location interception length is parameter 2 characters	exchange parameter 1 and parameter 2 and then the interception
Parameter / Result	3	-3	3456		012
Description	parameter 2 is negative		negative characters from the start to the end position	as length 0 , returns an empty string	exchange parameters , negative as 0
Parameter / Result	3	21	3456789	3456789	3456789
Description	parameter 2 is greater than or equal to the length of the string		as string length , the results with omitted parameters 2
Parameter / Result	3	NaN			012
Description	parameter 2 non- valid value		non- valid value as 0 , returns an empty string	non- valid value as 0 , because the empty string of length 0	non- valid value as 0 , the exchange parameter interception
Parameter / Result	-7	-3	3456
Description	parameter 1 and parameter 2 is negative		calculated from the end of the string position	length is negative, returns an empty string	negative as 0 , returns an empty string
Parameter / Result	-7	7	3456	3456789	0123456
Description	parameter 1 is a positive number , parameter 2 is negative		( automatically applied on top of the rules , do not explain )

  

* calculate the position from the end of the string : -1 refers to the last character in the string , -2 means the second last character , and so on ; also visible string length is the sum of the negative of the position, if the result is less than 0 , it is considered 0 .

  

  

contrast from the above table is not difficult to see that the main difference between the three methods are as follows :

  

   
• three method parameter represents a substring starting position , parameter 2 , said the slice and substring end position , and in behalf of substr is a substring of length ;
   
• For negative attitude , when there is a position in the parameter , slice , and substr from the end , and the end of substring does not support direct counting method as 0 ; When the parameter 2 position , slice and substring of dealing with parameter 1 : the former from the end , which is converted to 0, and then , as the negative substr returns an empty string of length 0 ;
   
• parameter 2 for parameter 1 is less than the case , substring biggest difference is that it will exchange two parameters and then intercept substring , substr because the second parameter indicates the length therefore no exception , slice Knots whole story is still normal substring search position, if the starting position at the end behind the empty string is returned .
  

  

According MDN right substr description , in IE may not support negative calculated from the end way .

  

   Finally, three methods yourself to try the effect of it:    

                                                                                                                                           

string	parameter 1	parameter 2	run	slice	substr	substring
				iderzheng	iderzheng.com	iderzheng

  

  

      

  

   

References:

   

    
1. String - JavaScript | MDN
    
2. What is the difference between String.slice and String.substring in JavaScript? - Stack Overflow
    
3. Slice vs Substr vs Substring vs [] Methods · jsPerf
   

  

     

      

 

 

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