Function Repository Resource:

HighlightCases

Source Notebook

Visualize cases of matched patterns in any expression

Contributed by: Michael Sollami

ResourceFunction["HighlightCases"][expr,pattern]

displays expr with matching cases highlighted.

ResourceFunction["HighlightCases"][expr,pattern,levelspec]

displays expr with matching cases highlighted on levels specified by levelspec.

Details and Options

Like Cases, ResourceFunction["HighlightCases"] takes the option Heads (True by default) which specifies whether to match within expression heads.

Also like Cases, the second argument can include Rule and RuleDelayed expressions. The right-hand side of a rule indicates the styling used to highlight the corresponding matches.

When specifing multiple patterns, use a List to style matches with different colors and use Alternatives for the same color.

Examples

Basic Examples (5)

Highlight cases in a List:

In[1]:=

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Use a list of patterns to style matching cases with multiple colors:

In[2]:=

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Highlight all the primes:

In[3]:=

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Use delayed rules for custom highlight styles:

In[4]:=

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Highlight heads in held expressions:

In[5]:=

$ResourceFunction["HighlightCases"][ HoldForm[\[Pi] + E*I + 1*(2 + 3)], {Plus, Times}, {3, 4}]$

Out[5]=

Scope (4)

Highlight matching cases on specific levels:

In[6]:=

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Use multiple highlight styles with overlapping patterns:

In[7]:=

$ResourceFunction[ "HighlightCases"][{{1, 2}, {3, 4}}, {_Integer -> Green, {_, _} -> Blue}]$

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Restrict HighlightCases to match only on levels 0 to 1:

In[8]:=

$ResourceFunction[ "HighlightCases"][{1, {2, {3}}}, _List -> Automatic, {0, 1}]$

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Restrict HighlightCases to match only on level 2:

In[9]:=

$ResourceFunction["HighlightCases"][ Range[25], {_?(Mod[#, 3] == 0 &), _?(Mod[#, 5] == 0 &)}]$

Out[9]=

Possible Issues (2)

Using a list of patterns in the second argument of HighlightCases will match each of the elements in the list:

In[10]:=

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Use HoldPattern to treat the list as a single pattern:

In[11]:=

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Publisher

Michael Sollami

Version History

1.0.0 – 23 April 2020

Related Resources

License Information

This work is licensed under a Creative Commons Attribution 4.0 International License