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Mathematica > Core Language > Rules & Patterns > Pattern Matching Functions > Cases >

Cases

gives a list of the

that match the pattern.

Cases

gives a list of the values of rhs corresponding to the

that match the pattern.

Cases

gives a list of all parts of expr on levels specified by levelspec that match the pattern.

Cases

gives the values of rhs that match the pattern.

Cases

gives the first n parts in expr that match the pattern.

MORE INFORMATION

The first argument to Cases need not have head List.

Cases evaluates rhs only when the pattern is found.

Cases uses standard level specifications:

	n	levels through n
	Infinity	levels through Infinity
	{n}	level n only
	{n₁,n₂}	levels through

The default value for levelspec in Cases is .

A positive level n consists of all parts of expr specified by n indices.

A negative level -n consists of all parts of expr with depth n.

Level consists of numbers, symbols and other objects that do not have subparts.

Level corresponds to the whole expression.

With the option setting Heads->True, Cases looks at heads of expressions, and their parts.

Cases traverses the parts of expr in a depth-first order, with leaves visited before roots.

EXAMPLES

CLOSE ALL

Basic Examples (2)

Find cases that explicitly match integers:

Find cases that do not match integers:

Return the

from inside each

matched:

Find cases that explicitly match integers:

In[1]:=

Out[1]=

Find cases that do not match integers:

In[2]:=

Out[2]=

Return the

from inside each

matched:

In[1]:=

Out[1]=

Scope (4)

Find all cases of lists of two elements:

Find the sum of every pair of elements:

Pick out elements that are not

Pick out cases of integers down to level 2:

Use

to evaluate only after explicit elements have been found: