Share the javascript judgment integer method, javascript integer

Share the javascript judgment integer method, javascript integer

There are two methods to judge integers: Regular Expression and verbatim expression.

Because the efficiency of the word-by-word judgment is too low, we will not describe it here. interested viewers can Google themselves.

1. Regular Expression judgment

Copy codeThe Code is as follows:
Var r =/^ \ +? [1-9] [0-9] * $/; // positive integer
Console. log (r. test (1.23 ));

Performance test:
Http://jsfiddle.net/wzsdp9Lc/

Extended feature list

Copy codeThe 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. Integer judgment

The idea of this method is to get an integer and determine whether it is equal to the original value.

Copy codeThe Code is as follows:
Var num = 1.23;
If (parseInt (num )! = Num ){
Console. log (num + "non-integer ");
}
Else {
Console. log (num + "integer ");
}

Performance Testing
Http://jsfiddle.net/euvn0L1g/1/