Averages/Arithmetic mean: Difference between revisions
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m (→[[Mean#ALGOL 68]]: clarify what ELLA ALGOL 68 is missing.) |
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This implementation uses a plain old static array of <tt>double</tt>s for the numeric vector. |
This implementation uses a plain old static array of <tt>double</tt>s for the numeric vector. |
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<c>#include <stdio.h> |
<lang c>#include <stdio.h> |
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double mean(double *p, unsigned qty) |
double mean(double *p, unsigned qty) |
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{double test[6] = {1.0, 2.0, 5.0, -5.0, 9.5, 3.14159}; |
{double test[6] = {1.0, 2.0, 5.0, -5.0, 9.5, 3.14159}; |
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printf("%lg\n", mean(test, 6)); |
printf("%lg\n", mean(test, 6)); |
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return 0;}</ |
return 0;}</lang> |
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=={{header|C++}}== |
=={{header|C++}}== |
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These functions return a float: |
These functions return a float: |
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<ocaml>let mean_floats xs = |
<lang ocaml>let mean_floats xs = |
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if xs = [] then |
if xs = [] then |
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0. |
0. |
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List.fold_left (+.) 0. xs /. float_of_int (List.length xs) |
List.fold_left (+.) 0. xs /. float_of_int (List.length xs) |
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let mean_ints xs = mean_floats (List.map float_of_int xs)</ |
let mean_ints xs = mean_floats (List.map float_of_int xs)</lang> |
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the previous code is easier to read and understand, though if you which |
the previous code is easier to read and understand, though if you which |
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would rather be handled by an exception. |
would rather be handled by an exception. |
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<ocaml>let mean_floats xs = |
<lang ocaml>let mean_floats xs = |
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if xs = [] then |
if xs = [] then |
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invalid_arg "empty list" |
invalid_arg "empty list" |
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in |
in |
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(float total /. length) |
(float total /. length) |
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;;</ |
;;</lang> |
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=={{header|Perl}}== |
=={{header|Perl}}== |
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<perl>sub avg { |
<lang perl>sub avg { |
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@_ or return 0; |
@_ or return 0; |
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my $sum = 0; |
my $sum = 0; |
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} |
} |
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print avg(qw(3 1 4 1 5 9)), "\n";</ |
print avg(qw(3 1 4 1 5 9)), "\n";</lang> |
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{{libheader|Data::Average}} |
{{libheader|Data::Average}} |
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With module Data::Average. |
With module Data::Average. |
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(For zero-length arrays, returns the empty list.) |
(For zero-length arrays, returns the empty list.) |
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<perl>use Data::Average; |
<lang perl>use Data::Average; |
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my $d = Data::Average->new; |
my $d = Data::Average->new; |
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$d->add($_) foreach qw(3 1 4 1 5 9); |
$d->add($_) foreach qw(3 1 4 1 5 9); |
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print $d->avg, "\n";</ |
print $d->avg, "\n";</lang> |
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=={{header|PHP}}== |
=={{header|PHP}}== |
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<php>$nums = array(3, 1, 4, 1, 5, 9); |
<lang php>$nums = array(3, 1, 4, 1, 5, 9); |
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if ($nums) |
if ($nums) |
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echo array_sum($nums) / count($nums), "\n"; |
echo array_sum($nums) / count($nums), "\n"; |
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else |
else |
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echo "0\n";</ |
echo "0\n";</lang> |
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=={{header|Pop11}}== |
=={{header|Pop11}}== |
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=={{header|Python}}== |
=={{header|Python}}== |
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{{works with|Python|2.5}} |
{{works with|Python|2.5}} |
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<python>def average(x): |
<lang python>def average(x): |
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return sum(x)/float(len(x)) if x else 0 |
return sum(x)/float(len(x)) if x else 0 |
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print average([3,1,4,1,5,9])</ |
print average([3,1,4,1,5,9])</lang> |
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Output: |
Output: |
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<python>3.83333333333333</ |
<lang python>3.83333333333333</lang> |
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{{works with|Python|2.4}} |
{{works with|Python|2.4}} |
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<python>def avg(data): |
<lang python>def avg(data): |
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if len(data)==0: |
if len(data)==0: |
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return 0 |
return 0 |
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else: |
else: |
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return sum(data)/float(len(data)) |
return sum(data)/float(len(data)) |
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print avg([3,1,4,1,5,9])</ |
print avg([3,1,4,1,5,9])</lang> |
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Output: |
Output: |
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<python>3.83333333333333</ |
<lang python>3.83333333333333</lang> |
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=={{header|Ruby}}== |
=={{header|Ruby}}== |
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<ruby>nums = [3, 1, 4, 1, 5, 9] |
<lang ruby>nums = [3, 1, 4, 1, 5, 9] |
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nums.empty? ? 0 : nums.inject(:+) / Float(nums.size)</ |
nums.empty? ? 0 : nums.inject(:+) / Float(nums.size)</lang> |
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=={{header|Scheme}}== |
=={{header|Scheme}}== |
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<scheme>(define (mean l) |
<lang scheme>(define (mean l) |
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(if (null? l) |
(if (null? l) |
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0 |
0 |
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(/ (apply + l) (length l))))</ |
(/ (apply + l) (length l))))</lang> |
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> (mean (list 3 1 4 1 5 9)) |
> (mean (list 3 1 4 1 5 9)) |
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