Error Messages/43860

Error Message

The «position» parameter of Unique() cannot be used when the index parameter is omitted.

Description

The Unique function has an optional index parameter and an optional «position» parameter. The «position» parameter can only be used when the index parameter is specified. So, for example, when you specify an index, you can use:

Unique(a, I, position: true)    {return position along I}

Unique(a, I, position: false)    {return the label in I}

Unique(a, I)         {return the label in I}

Without the index,

Unique(a)    {return the unique elements in a, across all dimensions}

Without the index parameter, the value returned is from the array a, not a value from an index (or indexes), so the «position» parameter is not meaningful.

See Also

• Unique
• Function calls and parameters
• Index
• Associative vs. Positional Indexing