#APL NARS 35 chars r←v a;c r←c←0 A:r+←1⋄c+←r≠⍎⌽⍕r⋄→A×⍳c<a it is the function v; "⍎⌽⍕"r traslate number r in string, reverse that string, traslate from string to number. Test and help functions: ⍝ return the one string for the basic types ('Char', 'Int', 'Float', 'Complex or Quaternion or Oction') ⍝ or one string for composite types ('Tensor 3' 'Tensor 4' etc 'Matrix', 'List', 'String') ⍝ follow the example in: https://codegolf.stackexchange.com/a/39745 type←{v←⍴⍴⍵⋄v>2:'Tensor ',⍕v⋄v=2:'Matrix'⋄(v=1)∧''≡0↑⍵:'String'⋄''≡0↑⍵:'Char'⋄v=1:'List'⋄⍵≢+⍵:'Complex or Quaternion or Oction'⋄⍵=⌈⍵:'Int'⋄'Float'} h←{'Int'≢type ⍵:¯1⋄(⍵<1)∨⍵>2e5:¯1⋄v ⍵} h 1 10 h 1.32 ¯1 h 7878 8057 h¨3 5 12 13 15 23 h 6 7 8 ¯1 h '123' ¯1 h '1' ¯1 h 1.0 10 h 1.0003 ¯1 h ¯2 ¯1 h 0 ¯1 h 200000 201200 h 200001 ¯1