In today’s post, you can sort of think of this as a related post towards the last one. I have alluded to how numbers can actually be a data type of text depending on how they enter your program or are created. We need some ways to deal with these scenarios. JavaScript gives us some.
number()
The number function/method allows us to take a number that is text and convert is to an integer. If text is passed to the function, it will return NaN. It will also convert boolean to 1 or 0.
[code lang=”js”]
// Create a text number variable
var myNum = "10";
myNum = number(myNum);
var myNum = true;
myNum = number(myNum);
// Code would return 1
var myNum = "123abc";
myNum = number(myNum);
// Code would return NaN
[/code]
parseFloat()
The parseFloat function/method returns a floating point number. It looks at the data, determines if the first character is a number, then it parses the string until it reaches a non-number. This could be a space or text. If the first character is text, it returns NaN.
[code lang=”js”]
// Create a text variable
var myNum = "10";
myNum = parseFloat(myNum);
// Code would return the integer 10
myNum = "10.123";
myNum = parseFloat(myNum);
// Code would return the integer 10.123
myNum = "10 abc";
myNum = parseFloat(myNum);
// Code would return the integer 10
myNum = "abc 10";
myNum = parseFloat(myNum);
// Code would return NaN
[/code]
parseInt()
The parseInt function will parse through a string and return a number just like parseFloat, except it will not return floating numbers. All other rules apply though.
[code lang=”js”]
// Create a text variable
var myNum = "10";
myNum = parseInt (myNum);
// Code would return the integer 10
myNum = "10.123";
myNum = parseInt (myNum);
// Code would return the integer 10
myNum = "10 abc";
myNum = parseInt (myNum);
// Code would return the integer 10
myNum = "abc 10";
myNum = parseInt (myNum);
// Code would return NaN
[/code]
Happy Coding!
Clay Hess
