+ Add∘ After∙ Alternant∧ And∡ Arctangent⎕ Array Input@ At⍥ At Depth⍤ At Rank⍤ Atop⍛ Before∘ Bind! Binomialᑣ Boxed⊕ Cartesian× Case| Case Fold⍪ Catenate⌈ Ceiling⍞ Character Input⍨ Commute+ Conjugate⍨ Constant⋷ Count? Deal⊥ Decodeⵧ Decrement⍛ Default Bind∨ Demote≡ Depth⊩ Dex~ Difference× Direction÷ Divide↓ Drop⍨ Duplicate¨ Eachᐵ Each Leftᑈ Each Right∊ Element Of∻ Empty Dictionary⍬ Empty Vector⊂ Enclose⊤ Encode∊ Enlist= Equal To⍎ Execute* Exponential! Factorial⍷ Find⊃ First⌊ Floor⍆ Fold⍅ Fold Back«» Fork⍕ Format⊇ From‥ From Inverted Table‥ From Keys And Values߹ From Pairs⍒ Grade Down⍋ Grade Up> Greater Than≥ Greater Than or Equal To∨ Greatest Common Divisor⫇ Group⋷ Histogram⫤ Ident≡ Identicalℑ Imaginary Part⧺ Increment⌷ Index⍳ Index Generator⍳ Index Of∙ Inner Product∩ Intersection⍸ Interval Index⍉ Inverted Table⍪ Join⌸ Key⌸ Key With Vocabulary߹ Key-Value Pair↓ Key-Value Pairs⊃ Keys, Laminate⊇ Last∧ Least Common Multiple⊣ Left⇾ Left Fork⊸ Left Hook< Less Than≤ Less Than or Equal To⫣ Lev⍟ Logarithm⌊ Lowercase| Magnitude↓ Major Cells⌹ Matrix Divide⌹ Matrix Inverse↾ Maximal⌈ Maximum⇂ Minimal⌊ Minimum⸚ Mirror↑ Mix× Multiply⍲ Nand⍟ Natural Logarithm- Negate⊆ Nest⍱ Nor~ Not≠ Not Equal To≢ Not Identical≠ Nub Sieve◡ On Cellsᑒ On Contents↡ On Infixes↟ On Outfixes↟ On Prefixes◠ On Scalars⌓ On Simple Scalars↡ On Suffixes… One Range∨ Or⍥ Over⍮ Pair⊆ Partition⊂ Partitioned Enclose∡ Phase⊃ Pick⊗ Polar* Power⊲ Precedes⊴ Precedes Or Identical∧ Promote⊕ Pure Imaginary↗ Raise… Rangeϼ Rank, Ravelℜ Real Part÷ Reciprocal⍆ Reduce⍅ Reduce Back| Remainder⍣ Repeat⌿ Replicateϼ Rerank⍴ Reshape⊖ Reverse⊢ Right⇽ Right Fork⟜ Right Hook? Roll√ Root⊖ Rotate⸠ Round⸠ Round To Nearest⍴ Shape⍮ Singleton⍒ Sort By Down⍋ Sort By Up⊵ Sort Down⊴ Sort Upⵧ Span√ Square Root⍞ Standard Error⎕ Standard Output⌺ Stencil- Subtract⊳ Succeeds⊵ Succeeds Or Identical§ Symmetric Difference⊞ Table↑ Take≢ Tally⍉ Transpose⍢ Under∪ Union∪ Unique⊗ Unit Polar⍣ Until⌈ Uppercase⁖ Valences⊇ Values⍸ Where⎕_BinFile Binary File⎕Assert Assert⎕CSV CSV⎕ct Comparison Tolerance⎕d Digits⎕Delay Delay⎕DT Date Time⎕Exists Exists⎕File File⎕HTTP HTTP⎕Import Import⎕io Index Origin⎕JSON JSON⎕l Lowercase Alphabet⎕math→Arccos Arccosine⎕math→Arcosh Hyperbolic Arcosine⎕math→Arcsin Arcsine⎕math→Arctan Arctangent⎕math→Arsinh Hyperbolic Arsine⎕math→Artanh Hyperbolic Artangent⎕math→Complementary Complementary⎕math→Cos Cosine⎕math→Cosh Hyperbolic Cosine⎕math→pi Pi⎕math→Sin Sine⎕math→Sinh Hyperbolic Sine⎕math→Tan Tangent⎕math→Tanh Hyperbolic Tangent⎕Repr Representation⎕seed Seed⎕systemInfo System Information⎕ts Timestamp⎕Type Type⎕u Uppercase Alphabet⎕Unicode Unicode⎕unix Unix Timestamp@ Atℑ Black Iℜ Black R⍉ Circle Backslash⊖ Circle Bar⊗ Circle Cross⍥ Circle Dots⊕ Circle Plus⍟ Circle Star߹ Colon Overbar∻ Colon Tilde, Comma⍪ Comma Bar× Cross- Dash⸚ Dash Dots⸠ Dash Stile⍢ Del Dots⍒ Del Stile⁖ Dot Colon¨ Dots↡ Double Down Arrow⫤ Double Left Tack« Double Left Wedgeⵧ Double Minus⧺ Double Plus» Double Right Wedge↟ Double Up Arrow↓ Down Arrow◡ Down Circle∪ Down Shoe⌊ Down Stile⊤ Down Tack⍕ Down Tack Jot∨ Down Wedge⍱ Down Wedge Tilde… Ellipsis∊ Epsilon⋷ Epsilon Overbar⍷ Epsilon Underbar= Equal≠ Equal Slash≡ Equal Underbar≢ Equal Underbar Slash! Exclamation Mark⌓ Half Circle⇂ Half Down Arrow↾ Half Up Arrow⍳ Iota⍸ Iota Underbar∘ Jot⍤ Jot Dots⍛ Jot Underbar⟜ Left Jot⊂ Left Shoeᑣ Left Shoe Dots⫇ Left Shoe Tilde⊆ Left Shoe Underbar⊣ Left Tack⫣ Left Tack Stile⊲ Left Triangle⊴ Left Triangle Underbar< Left Wedgeᑈ Left Wedge Dots≤ Left Wedge Underbar∡ Marked Angle∙ Middle Dot÷ Obelus+ Plus⎕ Quad⌺ Quad Diamond⌸ Quad Equal⌹ Quad Obelus⍞ Quad Quote? Question Mark⍴ Rhoϼ Rho Underbar⊸ Right Jot⊃ Right Shoeᑒ Right Shoe Dots⊇ Right Shoe Underbar⊢ Right Tack⊩ Right Tack Stile⊳ Right Triangle⊵ Right Triangle Underbar> Right Wedgeᐵ Right Wedge Dots≥ Right Wedge Underbar√ Root§ Section⍮ Semicolon Underbar⌿ Slash Bar⌷ Squad⊞ Square Plus* Star⍣ Star Dots| Stile⍋ Stile Delta⍅ Stile Left Arrow⍆ Stile Right Arrow~ Tilde⍨ Tilde Dots‥ Two Dots↑ Up Arrow◠ Up Circle↗ Up Right Arrow∩ Up Shoe⌈ Up Stile⊥ Up Tack⍎ Up Tack Jot∧ Up Wedge⍲ Up Wedge Tilde⇽ White Left Arrow⇾ White Right Arrow⍬ Zero Tilde⍸ Where r←⍸yy is an array of naturals. r is a vector containing all the indices of the elements of y, with a multiplicity equal to the element itself. This means that a 0 corresponds to that index not appearing in r, a 1 appearing once, a 2 appearing twice, et cetera.
y is a dictionary with natural values. r is a vector containing all keys of y, with a multiplicity equal to the corresponding value.