Hello everyone, in this article we will learn logical || and | operators. It is not language dependent. it is just logic and optimization. | and || both are called logical OR operator. Difference between them is in the way they are executed. The syntax for || and | is same.
Syntax:
Exp1 || Exp2 || Exp3 || ... ExpN
Exp1 | Exp2 | Exp3 | ... ExpN
Here Exp is Logical expression which returns either true or false.
Example:
A || B Results
False || False => True
False || True => True
True || False => True
True || True => False
It means if all expression returns true then end result will be true other wise false.
So what makes || and | different.
In case of || if first expression return false then it will execute next statement otherwise it will returns true. i.e. no more expressions will be further executed.
while in case of | all expression must be executed one by one.
let take an example to clear it more.
Validate and given number for empty or numeric only.
Create three methods IsEmpty returns true if given number is empty otherwise false.
IsNumber returns true if given number is of numeric type otherwise false.
IsEmptyOrNumber returns true if given number is either empty or numeric type.
const nl = '<br />';
var IsEmpty = function(a){
document.write('IsNotEmpty invoked! returns '+(a=='') + nl);
return (a=='')
}
var IsNumber = function(a){
document.write('IsNumber invoked! returns '+!isNaN(a) + nl);
return !isNaN(a);
}
var IsEmptyOrNumber = function(n){
if(IsEmpty(n) || IsNumber(n))
document.write(n+' is Valid Number'+nl);
else
document.write(n+' is InValid Number'+nl);
}
var n1 = '';
var n2 = '34';
var n3 = 'A34';
document.write('------------------------------------'+nl);
document.write('Validate Number: '+n1+nl);
IsEmptyOrNumber(n1);
document.write('------------------------------------'+nl);
document.write('Validate Number: '+n2+nl);
IsEmptyOrNumber(n2);
document.write('------------------------------------'+nl);
document.write('Validate Number: '+n3+nl);
IsEmptyOrNumber(n3);
Explanation:
When IsValid(n1); invoked IsEmpty() returns true and hence due to || logical OR operator, no more logical operation performed. only one method is invoked and will returns final result true.
for IsValid(n2); IsEmpty() returns false and next operation i.e. IsNumber() invoked which returns true. as shown in below result.
for IsValid(n3); IsEmpty() returns false and next operation i.e. IsNumber() invoked which returns false. as shown in below result.
OUTPUT: ------------------------------------ Validate Number: IsEmpty invoked! returns true is Valid Number ------------------------------------ Validate Number: 34 IsEmpty invoked! returns false IsNumber invoked! returns true 34 is Valid Number ------------------------------------ Validate Number: A34 IsEmpty invoked! returns false IsNumber invoked! returns false A34 is InValid Number
Now lets modify if(IsEmpty(n) || IsNumber(n)) to if(IsEmpty(n) | IsNumber(n))
const nl = '<br />';
var IsEmpty = function(a){
document.write('IsEmpty invoked! returns '+(a=='') + nl);
return (a=='')
}
var IsNumber = function(a){
document.write('IsNumber invoked! returns '+!isNaN(a) + nl);
return !isNaN(a);
}
var IsEmptyOrNumber = function(n){
if(IsEmpty(n) | IsNumber(n))
document.write(n+' is Valid Number'+nl);
else
document.write(n+' is InValid Number'+nl);
}
var n1 = '';
var n2 = '34';
var n3 = 'A34';
document.write('------------------------------------'+nl);
document.write('Validate Number: '+n1+nl);
IsEmptyOrNumber(n1);
document.write('------------------------------------'+nl);
document.write('Validate Number: '+n2+nl);
IsEmptyOrNumber(n2);
document.write('------------------------------------'+nl);
document.write('Validate Number: '+n3+nl);
IsEmptyOrNumber(n3);
Explanation:
When IsValid(n1); invoked IsEmpty() returns true and due to | logical OR operator, next operation i.e. IsNumber() invoked which returns true and makes final result true i.e Valid.
for IsValid(n2); IsEmpty() returns false and next operation i.e. IsNumber() invoked which returns true and makes final result true i.e Valid.
for IsValid(n2); IsEmpty() returns false and next operation i.e. IsNumber() invoked which returns false and makes final result false i.e InValid. as shown in below result.
OUTPUT: ------------------------------------ Validate Number: IsEmpty invoked! returns true IsNumber invoked! returns true is Valid Number ------------------------------------ Validate Number: 34 IsEmpty invoked! returns false IsNumber invoked! returns true 34 is Valid Number ------------------------------------ Validate Number: A34 IsEmpty invoked! returns false IsNumber invoked! returns false A34 is InValid Number
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