Averages/Median: Difference between revisions
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return list.get((list.size()-1)/2); |
return list.get((list.size()-1)/2); |
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}</lang> |
}</lang> |
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=={{header|Ruby}}== |
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<lang ruby>def median(ary) |
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return nil if ary.empty? |
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mid, rem = ary.length.divmod(2) |
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if rem == 0 |
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ary.sort[mid-1,2].inject(:+) / 2.0 |
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else |
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ary.sort[mid] |
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end |
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end |
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p median([]) # => nil |
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p median([5,3,4]) # => 4 |
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p median([5,4,2,3]) # => 3.5 |
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p median([3,4,1,-8.4,7.2,4,1,1.2]) # => 2.1</lang> |
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=={{header|Tcl}}== |
=={{header|Tcl}}== |
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Revision as of 14:30, 12 June 2009
You are encouraged to solve this task according to the task description, using any language you may know.
Write a program to find the median value of a vector of floating-point numbers. The program need not handle the case where the vector is empty, but must handle the case where there are an even number of elements.
See also
Java
<lang java5>public static double median(List<Double> list){
Collections.sort(list);
if(list.size() % 2 == 0){
return (list.get((list.size()) / 2) + list.get((list.size()) / 2 - 1)) / 2;
}
return list.get((list.size()-1)/2);
}</lang>
Ruby
<lang ruby>def median(ary)
return nil if ary.empty? mid, rem = ary.length.divmod(2) if rem == 0 ary.sort[mid-1,2].inject(:+) / 2.0 else ary.sort[mid] end
end
p median([]) # => nil p median([5,3,4]) # => 4 p median([5,4,2,3]) # => 3.5 p median([3,4,1,-8.4,7.2,4,1,1.2]) # => 2.1</lang>
Tcl
<lang tcl>proc median args {
set list [lsort -real $args]
set len [llength $list]
# Odd number of elements
if {$len & 1} {
return [lindex $list [expr {($len-1)/2}]]
}
# Even number of elements
set idx2 [expr {$len/2}]
set idx1 [expr {$idx2-1}]
return [expr {
([lindex $list $idx1] + [lindex $list $idx2])/2.0
}]
}
puts [median 3.0 4.0 1.0 -8.4 7.2 4.0 1.0 1.2]; # --> 2.1</lang>