# First

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**First** (`⊃`

, `↑`

) is a monadic function which extracts the first element in ravel order from its argument, or, if the argument is empty, returns its prototype. The glyph used varies by dialect. In a nested APL, First reduces the positive depth of an argument other than a simple scalar by at least one; in a flat APL it does not change the depth. A flat array language may also use the Head function to get the first major cell of its argument rather than the first 0-cell. In this case First can be obtained by taking the Head of the Ravel of the argument.

APL built-ins [edit]
| |||
---|---|---|---|

Primitive functions | |||

Scalar | |||

Monadic | Conjugate ∙ Not ∙ Roll ∙ Type | ||

Dyadic | Add ∙ Subtract ∙ Equal to (Xnor) ∙ Not Equal to (Xor) | ||

Non-Scalar | |||

Structural | Shape ∙ Reshape ∙ Tally ∙ Depth ∙ Ravel ∙ Reverse ∙ Raze ∙ Mix ∙ Cut (K) | ||

Selection | Take ∙ Drop ∙ Unique ∙ Identity | ||

Selector | Interval Index | ||

Computational | Match ∙ Not Match ∙ Nub Sieve | ||

Primitive operators | Each | ||

Quad names | |||

Arrays | Index origin ∙ Migration level | ||

Functions | |||

Operators | |||

Other | Zilde ∙ High minus ∙ Function axis |