## $DATA## M[UMPS] by Example |

Introduced in the 1977 ANSI M[UMPS] language standard.

This function returns a code that describes the existence of descendants and values of variables.

Assume that the following elements of `Y` are defined:

`Y(0)=0
Y(1)=1
Y(2)=2
Y(1,2,3)=123`

Then the function $Data will return the following results:

`Y(0)` has a value and no elements exist with indices like
(0,...):

Reference | Value | |
---|---|---|

$Data(Y(0)) |
1 |

`Y(1)` has a value and at least one element exists with
indices like (1,...), viz. `Y(1,2,3)`:

Reference | Value | |
---|---|---|

$Data(Y(1)) |
11 |

`Y(2)` has a value and no elements exist with indices like
(2,...):

Reference | Value | |
---|---|---|

$Data(Y(2)) |
1 |

`Y(1,2)` has no value, but at least one element exists
with indices like (1,2,...), viz. `Y(1,2,3)`:

Reference | Value | |
---|---|---|

$Data(Y(1,2)) |
10 |

`Y(1,2,3)` has a value and no elements exist with indices
like (1,2,3,...):

Reference | Value | |
---|---|---|

$Data(Y(1,2,3)) |
1 |

Assume that no local variables exist and that each new example (except for the last) adds a new element to the set.

Reference | Value | |
---|---|---|

Conditions: | Function-values: | |

Y not defined |
$Data(Y)=0 | |

Set Y=100 |
$Data(Y)=1 | |

Set Y="AB" |
$Data(Y)=1 | |

Set A(1)="ABC" |
$Data(A(1))=1 | |

$Data(A)=10 | ||

Set B(1,2)="BC" |
$Data(B(1,2))=1 | |

$Data(B(1))=10 | ||

$Data(B))=10 | ||

Set B(1)="CD" |
$Data(B(1))=11 | |

Kill B(1,2) |
$Data(B(1,2))=0 | |

$Data(B(1))=1 | ||

$Data(B)=10 |

$Data with a global variable as the parameter:

Examples with naked references:

Command | Value ofX |
Value of thenaked indicator |
---|---|---|

Set X=$Data(^A) |
10 |
not defined |

Set X=$Data(^(1)) |
error | not defined |

Set X=$Data(^A(1)) |
10 |
"^A(" |

Set X=$Data(^A(99)) |
0 |
"^A(" |

Set X=$Data(^A(1)) |
10 |
"^A(" |

Set X=$Data(^(1,2)) |
10 |
"^A(1," |

Set X=$Data(^(2)) |
10 |
"^A(1," |

Set X=$Data(^(2,3)) |
1 |
"^A(1,2," |

Set X=$Data(^3)) |
1 |
"^A(1,2," |

Set X=$Data(^(4)) |
0 |
"^A(1,2," |

Set X=$Data(^A(1,2)) |
10 |
"^A(1," |

Set ^A(1,2,3,4)="" |
"^A(1,2,3," | |

Set X=$Data(^A(1,2,3)) |
11 |
"^A(1,2," |

$Data(GLVN)

`Set ^ABC(1,2)="reset naked indicator"`

; naked indicator is now `^ABC(1,
Set ^(3,4)=$Data(^(5,6))`

; 1. fetch ^(5,6) =

; 2. store ^(3,4) =

; naked indicator is now:

Copyright © Standard Documents; 1977-2017 MUMPS Development Committee;

Copyright © Examples: 1995-2017 Ed de Moel;

Copyright © Annotations: 2003-2017 Jacquard Systems Research.

*The information in this page is
NOT authoritative and subject to be modified
at any moment.Please consult the
appropriate (draft) language standard for an
authoritative definition.*

*Some specifications are "approved
for inclusion in a future standard". Note
that the MUMPS Development Committee cannot
guarantee that such future standards will
indeed be published.*

This page most recently updated on 13-Sep-2014, 12:06:03 .

For comments, contact Ed de Moel (demoel@jacquardsystems.com)