Factors of an integer: Difference between revisions
(→{{header|Python}}: (loops up to n/2)) |
m (→{{header|Ruby}}: optimization) |
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[1, 3, 5, 9, 15] |
[1, 3, 5, 9, 15] |
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As we only have to loop up to <math>\sqrt{n}</math>, we can write |
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<lang ruby>class Integer |
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def factors() |
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2.upto(Math.sqrt(self)).select {|i| (self % i).zero?} \ |
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.inject([1]) {|f, i| f << i << self/i} \ |
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.sort |
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end |
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end |
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p 45.factors</lang> |
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[[Category:Arithmetic operations]] |
[[Category:Arithmetic operations]] |
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{{basic data operation}} |
{{basic data operation}} |
Revision as of 16:53, 15 August 2009
You are encouraged to solve this task according to the task description, using any language you may know.
Compute the factors of a number.
Clojure
<lang lisp>(defn factors [n] (filter #(zero? (rem n %)) (range 1 n)))
(print (factors 45))</lang>
(1 3 5 9 15)
Python
<lang python>>>> def factors(n): return [i for i in range(1,n//2) if not n%i]
>>> factors(45) [1, 3, 5, 9, 15]</lang>
Ruby
<lang ruby>class Integer
def factors() (1..self - 1).select { |n| (self % n).zero? } end
end p 45.factors</lang>
[1, 3, 5, 9, 15]
As we only have to loop up to , we can write <lang ruby>class Integer
def factors() 2.upto(Math.sqrt(self)).select {|i| (self % i).zero?} \ .inject([1]) {|f, i| f << i << self/i} \ .sort end
end p 45.factors</lang>
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |
Comparison |
Matching
Memory Operations
Pointers & references |
Addresses