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{{Built-in|Format|⍕}} is a [[primitive function]].
{{Built-in|Format|⍕}} is an [[ambivalent]] [[primitive function]] which formats the right [[argument]] into a [[simple]] [[character]] array, optionally following the specification supplied as the left argument. The usage of the left argument varies across implementations.


== Examples ==
== Examples ==


Format in its [[monadic]] form, allows the user to convert [[Array model|arrays]] of any [[type]] into [[simple]] character arrays (for example for concatenation with other character arrays):
=== Monadic form ===
 
Format in its [[monadic]] form allows the user to convert [[Array model|arrays]] of any [[type]] into simple character arrays (for example for concatenation with other character arrays). The result usually matches the interpreter's default display, either by <source lang=apl inline>⎕←</source> or by REPL.
 
<source lang=apl>
<source lang=apl>
       supper ← 10
       supper ← 10
       'I ate ',(⍕supper),' shrimp.'
       'I ate ',(⍕supper),' shrimp.'
I ate 10 shrimp.
I ate 10 shrimp.
      ⎕←DATA←(⍳3) (2 2⍴⍳4) 'TEXT' 100
1 2 3  1 2  TEXT 100
        3 4
      ⍕DATA
1 2 3  1 2  TEXT 100
        3 4
      (⍴DATA) (⍴⍕DATA)
4  2 22
</source>
</source>
It is very powerful when combined with [[Execute]], allowing the user to construct APL code:
 
=== Dyadic form ===
 
The [[dyadic]] form of Format varies across implementations.
 
[[Dyalog APL]] and [[NARS2000]] support column width and the number of decimal places for formatting [[numeric]] arrays. The following example formats the 2-by-3 array with 12 spaces per column, rounded to 2 decimal places:
 
<source lang=apl>
      ⎕←C←2 3⍴ 32.10958 0 ¯101.4914 ¯99.40878 ¯101.872 1001.48173
32.10958    0    ¯101.4914
¯99.40878 ¯101.872 1001.48173
      ⍴C
2 3
 
      12 2⍕C
      32.11        0.00    ¯101.49
      ¯99.41    ¯101.87    1001.48
      ⍴(12 2⍕C)
2 36
</source>{{Works in|[[Dyalog APL]], [[NARS2000]]}}
 
[[APLX]] supports '''Format by example''', which uses string left argument for a rich set of format specifications:
 
<source lang=apl>
<source lang=apl>
      data ← 7
      '55.55' ⍕22.234 1.398 11.00
      ⍎'6 × ',⍕data
22.23 1.4 11
42
      '55.55 5.555 55.55 55'⍕22.234 1.398 0.00 11.0
</source>
22.23 1.398      11
      '555,555,555.55'⍕1234567.89
  1,234,567.89
</source>{{Works in|[[APLX]]}}
 
== External links ==
 
=== Documentation ===
 
* Dyalog [http://help.dyalog.com/latest/#Language/Primitive%20Functions/Format%20Monadic.htm monadic], [http://help.dyalog.com/latest/#Language/Primitive%20Functions/Format%20Dyadic.htm dyadic]
* [http://wiki.nars2000.org/index.php/Symbol_Format NARS2000]
* APLX [http://microapl.com/apl_help/ch_020_020_680.htm monadic], [http://microapl.com/apl_help/ch_020_020_690.htm by specification], [http://microapl.com/apl_help/ch_020_020_700.htm by example]
* J [https://www.jsoftware.com/help/dictionary/d602.htm Dictionary], [https://code.jsoftware.com/wiki/Vocabulary/quoteco NuVoc]
 
{{APL built-ins}}[[Category:Primitive functions]]
{{APL built-ins}}[[Category:Primitive functions]]

Revision as of 06:32, 12 June 2020

⍕

Format (⍕) is an ambivalent primitive function which formats the right argument into a simple character array, optionally following the specification supplied as the left argument. The usage of the left argument varies across implementations.

Examples

Monadic form

Format in its monadic form allows the user to convert arrays of any type into simple character arrays (for example for concatenation with other character arrays). The result usually matches the interpreter's default display, either by ⎕← or by REPL. 

      supper ← 10
      'I ate ',(⍕supper),' shrimp.'
I ate 10 shrimp.

      ⎕←DATA←(⍳3) (2 2⍴⍳4) 'TEXT' 100
 1 2 3   1 2   TEXT 100
         3 4
      ⍕DATA
 1 2 3   1 2   TEXT 100
         3 4
      (⍴DATA) (⍴⍕DATA)
 4  2 22

Dyadic form

The dyadic form of Format varies across implementations.

Dyalog APL and NARS2000 support column width and the number of decimal places for formatting numeric arrays. The following example formats the 2-by-3 array with 12 spaces per column, rounded to 2 decimal places: 

      ⎕←C←2 3⍴ 32.10958 0 ¯101.4914 ¯99.40878 ¯101.872 1001.48173
 32.10958    0     ¯101.4914 
¯99.40878 ¯101.872 1001.48173
      ⍴C
2 3

      12 2⍕C
       32.11        0.00     ¯101.49
      ¯99.41     ¯101.87     1001.48
      ⍴(12 2⍕C)
2 36
Works in: Dyalog APL, NARS2000

APLX supports Format by example, which uses string left argument for a rich set of format specifications: 

      '55.55' ⍕22.234 1.398 11.00
22.23 1.4 11
      '55.55 5.555 55.55 55'⍕22.234 1.398 0.00 11.0
22.23 1.398       11
      '555,555,555.55'⍕1234567.89
  1,234,567.89
Works in: APLX

External links

Documentation


APL built-ins [edit]
Primitives (Timeline) Functions
Scalar
Monadic Conjugate ∙ Negate ∙ Signum ∙ Reciprocal ∙ Magnitude ∙ Exponential ∙ Natural Logarithm ∙ Floor ∙ Ceiling ∙ Factorial ∙ Not ∙ Pi Times ∙ Roll ∙ Type ∙ Imaginary ∙ Square Root
Dyadic Add ∙ Subtract ∙ Times ∙ Divide ∙ Residue ∙ Power ∙ Logarithm ∙ Minimum ∙ Maximum ∙ Binomial ∙ Comparison functions ∙ Boolean functions (And, Or, Nand, Nor) ∙ GCD ∙ LCM ∙ Circular ∙ Complex ∙ Root
Non-Scalar
Structural Shape ∙ Reshape ∙ Tally ∙ Depth ∙ Ravel ∙ Enlist ∙ Table ∙ Catenate ∙ Reverse ∙ Rotate ∙ Transpose ∙ Raze ∙ Mix ∙ Split ∙ Enclose ∙ Nest ∙ Cut (K) ∙ Pair ∙ Link ∙ Partitioned Enclose ∙ Partition
Selection First ∙ Pick ∙ Take ∙ Drop ∙ Unique ∙ Identity ∙ Stop ∙ Select ∙ Replicate ∙ Expand ∙ Set functions (Intersection ∙ Union ∙ Without) ∙ Bracket indexing ∙ Index ∙ Cartesian Product ∙ Sort
Selector Index generator ∙ Grade ∙ Index Of ∙ Interval Index ∙ Indices ∙ Deal ∙ Prefix and suffix vectors
Computational Match ∙ Not Match ∙ Membership ∙ Find ∙ Nub Sieve ∙ Encode ∙ Decode ∙ Matrix Inverse ∙ Matrix Divide ∙ Format ∙ Execute ∙ Materialise ∙ Range
Operators Monadic Each ∙ Commute ∙ Constant ∙ Replicate ∙ Expand ∙ Reduce ∙ Windowed Reduce ∙ Scan ∙ Outer Product ∙ Key ∙ I-Beam ∙ Spawn ∙ Function axis
Dyadic Bind ∙ Compositions (Compose, Reverse Compose, Beside, Withe, Atop, Over) ∙ Inner Product ∙ Determinant ∙ Power ∙ At ∙ Under ∙ Rank ∙ Depth ∙ Variant ∙ Stencil ∙ Cut ∙ Direct definition (operator)
Quad names Index origin ∙ Comparison tolerance ∙ Migration level ∙ Atomic vector
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