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FreeQ
FreeQ
[
expr
,
form
]
yields
True
if no subexpression in
expr
matches
form
, and yields
False
otherwise.
FreeQ
[
expr
,
form
,
levelspec
]
tests only those parts of
expr
on levels specified by
levelspec
.
MORE INFORMATION
form
can be a pattern.
FreeQ
uses standard level specifications:
n
levels
1
through
n
Infinity
levels
1
through
Infinity
{
n
}
level
n
only
{
n
1
,
n
2
}
levels
n
1
through
n
2
The default value for
levelspec
in
FreeQ
is
{0,
Infinity
}
.
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
-1
consists of numbers, symbols and other objects that do not have subparts.
Level
0
corresponds to the whole expression.
With the default option setting
Heads
->
True
,
FreeQ
looks at heads of expressions, and their parts.
EXAMPLES
CLOSE ALL
Basic Examples
(2)
Test whether a list is free of
0
:
In[1]:=
Out[1]=
FreeQ
normally tests all levels in an expression:
In[1]:=
Out[1]=
Scope
(1)
Applications
(2)
SEE ALSO
MemberQ
Count
StringFreeQ
TUTORIALS
Testing and Searching List Elements
Manipulating Expressions like Lists
Putting Constraints on Patterns
MORE ABOUT
Elements of Lists
Expressions
Pattern Matching Functions
New in 1
© 2008 Wolfram Research, Inc.
EXAMPLES
Basic Examples 
Scope 