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About the difference between substring() and substr() (detailed tutorial)
About the difference between substring() and substr() (detailed tutorial)
Below I will share with you an example based on the use and difference between substring() and substr(). It has a good reference value and I hope it will be helpful to everyone.
In JavaScript, interception is usually used. The so-called interception is actually to obtain the content from a certain position to a certain position of the intercepted element. Then JS provides me with the two substring and substr Method:
What is the difference between these two interception methods? Direct code demonstration:
substring(a,b):
a: indicates the starting position
b: Indicates the end position
! But it is worth noting: when intercepting, the intercepted content includes the element at the starting position, but does not include the element at the ending position!
Example:
function sub1(){
var str = 'javascript';
return str.substring(0,4);
}
console.log(sub1()); //返回值为‘java'
function sub2(){
var str = 'javascript';
return str.substring(1,4);
}
console.log(sub2()); //返回值为‘ava'Summary: When substring is intercepted, the starting position is included and the ending position is not included, and Both parameters a and b are positional values, that is, index values
substr (index, length):
index: Represents the starting position
length: Represents the length of the intercepted content
! The element at the starting position is included when intercepting!
Example:
function sub3(){
var str = 'javascript';
return str.substr(0,4);
}
console.log(sub3()); //返回值为‘java'
function sub4(){
var str = 'javascript';
return str.substr(1,4);
}
console.log(sub4()); //返回值为‘avas'Summary: When substr is intercepted, including the starting position, the two parameters are starting Starting position and interception length
! Pay attention to the distinction and use it wisely!
The above is what I compiled for everyone. I hope it will be helpful to everyone in the future.
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