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Programming-Idioms

  • Ada
  • Dart

Idiom #117 Get list size

Set n to the number of elements of the list x.

int n = x.length;
with Ada.Containers.Vectors;
use Ada.Containers;
N : Count_Type := X.Length;
int n;
int x[5];
n = sizeof(x)/sizeof(*x);

C doesn't have the higher level concept of lists at least as many may understand it, so this completes the prompt using C arrays. sizeof(array) will return the amount of bytes all the elements of the array are taking up and sizeof(var) will return the amount of bytes a single variable is taking up. *x in this example is the same as x[0]; it retrieves the first element of the array, so we're dividing the amount of bytes total for the array by the amount of bytes each element uses.
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programming-idioms.org 
int n = x.length;
N : Count_Type := X.Length;
int n;
int x[5];
n = sizeof(x)/sizeof(*x);
size_t n = sizeof(x)/sizeof(*x);
(def n (count x))
size_t n = x.size();
int n = x.Length;
int n = x.Count;
n = walkLength(x);
auto n = x.length;
n = Enum.count(x)
N = length(X).
n = size(x)
n := len(x)
def n = x.size()
let n = length x
var n = x.length;
int n = x.length;
int n = x.size();
val n = x.size
(setf n (length x))
local n = #x
NSUInteger n=x.count;
$n = count($x);
n := length(x);
my $N = @x;

$n = scalar @x;
length(x, N).
n = len(x)
n = x.length
let n = x.len();


val n = x.size
(define n (length x))
n := x size.
Dim n As Integer = x.Count
n = UBound(x) + 1