Smith numbers: Difference between revisions
→{{header|jq}}
Line 1,806:
Last 12 Smith Numbers below 10000:
9778 9840 9843 9849 9861 9880 9895 9924 9942 9968 9975 9985</pre>
=={{header|jq}}==
{{works with|jq}}
'''Works with gojq, the Go implementation of jq'''
''' Preliminaries'''
<lang jq>def is_prime:
. as $n
| if ($n < 2) then false
elif ($n % 2 == 0) then $n == 2
elif ($n % 3 == 0) then $n == 3
elif ($n % 5 == 0) then $n == 5
elif ($n % 7 == 0) then $n == 7
elif ($n % 11 == 0) then $n == 11
elif ($n % 13 == 0) then $n == 13
elif ($n % 17 == 0) then $n == 17
elif ($n % 19 == 0) then $n == 19
else {i:23}
| until( (.i * .i) > $n or ($n % .i == 0); .i += 2)
| .i * .i > $n
end;
def sum(s): reduce s as $x (null; . + $x);
# emit a stream of the prime factors as per prime factorization
def prime_factors:
. as $num
| def m($p): # emit $p with appropriate multiplicity
$num | while( . % $p == 0; . / $p )
| $p ;
if (. % 2) == 0 then m(2) else empty end,
(range(3; 1 + (./2); 2)
| select(($num % .) == 0 and is_prime)
| m(.));
</lang>
'''The task'''
<lang jq># input should be an integer
def is_smith:
def sumdigits:
tostring|explode|map([.]|implode|tonumber)| add;
(is_prime|not) and
(sumdigits == sum(prime_factors|sumdigits));
"Smith numbers up to 10000:\n",
(range(1; 10000) | select(is_smith))
</lang>
{{out}}
<pre>
Smith numbers up to 10000:
4
22
27
58
...
9942
9968
9975
9985
</pre>
=={{header|Julia}}==
| |||