A number that can be positive, negative, or zero.
The Number data type is useful for describing values such as position, size, and color. A number can be an integer such as 20 or a decimal number such as 12.34. For example, a circle's position and size can be described by three numbers:
circle(50, 50, 20);
circle(50, 50, 12.34);
Numbers support basic arithmetic and follow the standard order of operations: Parentheses, Exponents, Multiplication, Division, Addition, and Subtraction (PEMDAS). For example, it's common to use arithmetic operators with p5.js' system variables that are numbers:
// Draw a circle at the center.
circle(width / 2, height / 2, 20);
// Draw a circle that moves from left to right.
circle(frameCount * 0.01, 50, 20);
Here's a quick overview of the arithmetic operators:
1 + 2 // Add
1 - 2 // Subtract
1 * 2 // Multiply
1 / 2 // Divide
1 % 2 // Remainder
1 ** 2 // Exponentiate
It's common to update a number variable using arithmetic. For example, an object's location can be updated like so:
x = x + 1;
The statement above adds 1 to a variable x using the + operator. The addition assignment operator += expresses the same idea:
x += 1;
Here's a quick overview of the assignment operators:
x += 2 // Addition assignment
x -= 2 // Subtraction assignment
x *= 2 // Multiplication assignment
x /= 2 // Division assignment
x %= 2 // Remainder assignment
Numbers can be compared using the relational operators >, << code="">, >=, <=< code="">, ===, and !==. For example, a sketch's frameCount can be used as a timer:
if (frameCount > 1000) {
text('Game over!', 50, 50);
}
An expression such as frameCount > 1000 evaluates to a Boolean value that's either true or false. The relational operators all produce Boolean values:
2 > 1 // true
2 < 1 // false
2 >= 2 // true
2 <= 2="" true="" !="=" false="" <="" code=""/>See Boolean for more information about comparisons and conditions.
Note: There are also == and != operators with one fewer =. Don't use them.
Expressions with numbers can also produce special values when something goes wrong:
sqrt(-1) // NaN
1 / 0 // Infinity
The value NaN stands for Not-A-Number. NaN appears when calculations or conversions don't work. Infinity is a value that's larger than any number. It appears during certain calculations.