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Challenges

Comments on Make a frequency table (histogram)

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Make a frequency table (histogram)

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Challenge

Given an array in any suitable format, create a frequency table for it. i.e: Pair each unique element with the number of times it appears in the array.

You can return the frequency table as a list of pairs, hashmap/dictionary, output the pairs directly, etc.

Tests

{ 1 1 2 3 5 6 6 }           -> { { 1 2 } { 2 1 } { 3 1 } { 5 1 } { 6 2 } }
{ }                         -> { }
{ 1 6 7 1 2 6 6 1 53 4 10 } -> { { 1 3 } { 2 1 } { 4 1 } { 53 1 } { 6 3 } { 7 1 } { 10 1 } }
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Empty arrays (1 comment)
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JavaScript (Node.js), 38 32 bytes

-6 bytes thanks to Shaggy!

a=>a.map(v=>d[v]=-~d[v],d={})&&d

Try it online!

Basically just this but returning the result

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1 comment thread

[32 bytes](https://tio.run/##RY3BCoMwEETP5iv2JAmsUttqDxJ/RHIIxpQWa8QEL2J/PU1SSmHYGR7DzlNu0g7rY3HFbNTo... (1 comment)
[32 bytes](https://tio.run/##RY3BCoMwEETP5iv2JAmsUttqDxJ/RHIIxpQWa8QEL2J/PU1SSmHYGR7DzlNu0g7rY3HFbNTo...
Shaggy‭ wrote over 2 years ago