Are All Elements Equal?
Challenge
Given a list of integers >= 0 , check if all of them are equal.
Tests
[1,1,1,1,1] -> true
[0,1,1,6,7] -> false
[1] -> true
[] -> undefined(you do not need to handle this)
You may take the integers in any form(strings, list, codepoints, etc.)
You can output two distinct values for true or false, or simply a truthy or falsy value in your language.
Trivial builtins are allowed, but it is encouraged to edit them into the trivial builtins answer, or try a different approach.
Zsh, 8 bytes >$@ <^$ …
3y ago
Japt, 3 bytes e¡g Tr …
3y ago
[APL (Dyalog Unicode)], 3 byte …
3y ago
Rockstar, 76 bytes Takes in …
3y ago
[Python 3], 20 bytes …
3y ago
[Haskell], 16 bytes …
3y ago
[C (gcc)], 46 bytes …
3y ago
[Ruby], 15 bytes ```ruby - …
3y ago
[brainfuck], 40 bytes Outpu …
3y ago
JavaScript, 20 bytes Output …
3y ago
J, 4 bytes ``` -:|. ``` …
3y ago
Ruby, 14 bytes ```ruby ->{ …
3y ago
[Jelly], 1 byte E Tr …
3y ago
Trivial answers [Husk], 1 b …
3y ago
J, 5 char ``` 2>#. ``` …
2y ago
MATL, 4 bytes ``` tPX= ``` …
3y ago
16 answers
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JavaScript, 20 bytes
Outputs false for truthy and true for falsey.
a=>a.some(x=>x-a[0])
Outputs true and false as normal.
a=>new Set(a).size<2
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Zsh, 8 bytes
>$@
<^$1Outputs via exit code: 0 for not all the same; 1 for all the same
-
>$@: create a file named for each element in the input- effectively deduplicates because you can only have one file with a given name
-
<^$1: try to find a file with any name other than the first input. If there were at least two distinct inputs, this will succeed and return0, otherwise it will fail with status1
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APL (Dyalog Unicode), 3 bytes
⍋≡⍒
⍋ computes the permutation vector that would sort the argument into ascending order
⍒ computes the permutation vector that would sort the argument into descending order
If they are identical (≡), all elements must be equal.
See also this talk by Conor Hoekstra.
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Ruby, 15 bytes
->a{a.all?a[0]}
->a{ } # lambda taking array `a`
a.all? # do all items in the array match...
a[0] # ...the first?
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C (gcc), 46 bytes
f(int*a){return *a<0|a[1]<0||*a==a[1]&f(a+1);}
This takes an array that is terminated by a negative number (which is not part of the list content, just like the terminating \0 is not part of the string content in C strings).
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J, 4 bytes
-:|.
Checks if the input array matches itself reversed. This is a tacit form and is executed monadically as x f (g x).
Ruby, 14 bytes
->{_1|[]in[_]}
Alternative solution:
->a{!(a|a)[1]}
Couple of other solutions I developed:
->a{!a.uniq[1]} # 15 bytes
->{!(_1|[])[1]} # 15 bytes
->a{(a|a).one?} # 15 bytes
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Jelly, 1 byte
E
Boring builtin answer
Non builtin, the shortest I can get is 3 bytes:
ḷ\⁼
Here, we replace each element with the first element, then check if that is equal to the original array
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MATL, 4 bytes
tPX=
tPX=
t - duplicate with implicit input
P - fliplr in MATLAB, reverses top of stack
X= - isequal
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2 comment threads