JavaScript method sharing for judging integers_javascript skills

There are two ways to judge integers: regular judgment and literal judgment.

Since word-by-word judgment is too inefficient, it will not be described here. Interested readers can Google it themselves.

1. Regular judgment

Copy code The code is as follows:

var r = /^ ?[1-9][0-9]*$/; //Positive integer
console.log(r.test(1.23));

Effectiveness test:
http://jsfiddle.net/wzsdp9Lc/

Extended function list

Copy code The code is as follows:

"^\d $"　 //Non-negative integer (positive integer 0)
"^[0-9]*[1-9][0-9]*$" //Positive integer
"^((-\d )|(0 ))$" //Non-positive integer (negative integer 0)
"^-[0-9]*[1-9][0-9]*$" // Negative integer
"^-?\d $"　　 //Integer
"^\d (\.\d )?$" //Non-negative floating point number (positive floating point number 0)
"^(([0-9] \.[0-9]*[1-9][0-9]*)|([0-9]*[1-9][0-9]*\. [0-9] )|([0-9]*[1-9][0-9]*))$" //Positive floating point number
"^((-\d (\.\d )?)|(0 (\.0 )?))$" //Non-positive floating point number (negative floating point number 0)
"^(-(([0-9] \.[0-9]*[1-9][0-9]*)|([0-9]*[1-9][0-9]* \.[0-9] )|([0-9]*[1-9][0-9]*)))$" //Negative floating point number
"^(-?\d )(\.\d )?$" //Floating point number

2. Rounding judgment

The idea of ​​this method is to determine whether it is equal to the original value after rounding

Copy code The code is as follows:

var num=1.23;
if (parseInt(num) != num) {
console.log(num "is a non-integer");
}
else{
console.log(num "is an integer");
}

Effectiveness test
http://jsfiddle.net/euvn0L1g/1/