length -package:bytestring -package:text package:ghc

Returns the size/length of a finite structure as an Int. The default implementation just counts elements starting with the leftmost. Instances for structures that can compute the element count faster than via element-by-element counting, should provide a specialised implementation.

Examples

Basic usage:

>>> length []
0

>>> length ['a', 'b', 'c']
3

>>> length [1..]
* Hangs forever *

Returns the length of the FastString in characters

Return the length of a PtrString

(lengthAtLeast xs n) = (length xs >= n)

(lengthAtMost xs n) = (length xs <= n)

(lengthExceeds xs n) = (length xs > n)

(lengthIs xs n) = (length xs == n)

(lengthIsNot xs n) = (length xs /= n)

(lengthLessThan xs n) == (length xs < n)

Encode the argument in it's full length. This is different from many default binary instances which make no guarantee about the actual encoding and might do things use variable length encoding.

atLength atLen atEnd ls n unravels list ls to position n. Precisely:

atLength atLenPred atEndPred ls n
| n < 0         = atLenPred ls
| length ls < n = atEndPred (n - length ls)
| otherwise     = atLenPred (drop n ls)

True if length xs == length ys

True if length xs <= length ys

True if length xs < length ys