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(elisp)Numbers

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Numbers
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   GNU Emacs supports two numeric data types: "integers" and "floating
point numbers".  Integers are whole numbers such as -3, 0, 7, 13, and
511.  Their values are exact.  Floating point numbers are numbers with
fractional parts, such as -4.5, 0.0, or 2.71828.  They can also be
expressed in exponential notation: 1.5e2 equals 150; in this example,
`e2' stands for ten to the second power, and that is multiplied by 1.5.
Floating point values are not exact; they have a fixed, limited amount
of precision.

Integer Basics

Representation and range of integers.

Float Basics

Representation and range of floating point.

Predicates on Numbers

Testing for numbers.

Comparison of Numbers

Equality and inequality predicates.

Numeric Conversions

Converting float to integer and vice versa.

Arithmetic Operations

How to add, subtract, multiply and divide.

Rounding Operations

Explicitly rounding floating point numbers.

Bitwise Operations

Logical and, or, not, shifting.

Math Functions

Trig, exponential and logarithmic functions.

Random Numbers

Obtaining random integers, predictable or not.