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Mathematica > Core Language > Rules & Patterns > Patterns > Longest >

Longest

Longest[p]
is a pattern object that matches the longest sequence consistent with the pattern p.

If several Longest objects occur in the same expression, those that appear first are given higher priority to match longest sequences.

Longest is given priority pri to be the longest sequence. Matches for longest sequences are tried first for Longest objects with higher priorities.

Priorities can be any expression, and are ordered in standard Mathematica Sort order. Longest[p] specifies the highest possible priority.

Longest objects with equal priorities are tried in the order they appear in the expression.

If no explicit Longest or Shortest is given, ordinary expression patterns are normally effectively assumed to be Shortest[p], while string patterns are assumed to be Longest[p].

For ordinary expressions, Longest[p] specifies that not just p itself, but also all parts of p should match the longest sequences.

Require that

matches the longest sequence it can:

The default is to have earlier patterns match shortest sequences:

Require that

matches the longest sequence it can:

Out[1]=

The default is to have earlier patterns match shortest sequences:

Out[2]=

Use priorities to affect ambiguous choices:

Find the longest sequence of integers:

Consider the following variable length argument function:

Use Longest to express it as one pattern:

For strings, the default is to have earlier patterns match longest character sequences:

This is equivalent:

Priorities are not supported in string expressions: