Info Catalog elisp: Lisp Data Types elisp: Top elisp: Strings and Characters

elisp: Numbers

 
 3 Numbers
 *********
 
 GNU Emacs supports two numeric data types: “integers” and
 “floating-point numbers”.  Integers are whole numbers such as −3, 0, 7,
 13, and 511.  Floating-point numbers are numbers with fractional parts,
 such as −4.5, 0.0, and 2.71828.  They can also be expressed in
 exponential notation: ‘1.5e2’ is the same as ‘150.0’; here, ‘e2’ stands
 for ten to the second power, and that is multiplied by 1.5.  Integer
 computations are exact, though they may overflow.  Floating-point
 computations often involve rounding errors, as the numbers have a fixed
 amount of precision.
 

Menu

 
· 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.
 

Info Catalog elisp: Lisp Data Types elisp: Top elisp: Strings and Characters