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Clear
✖
Clear

✖
Clear[s1,s2,…]

clears values and definitions for the symbols si.

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Clear[patt1,patt2,…]

clears values and definitions for all symbols whose names textually match any of the arbitrary string patterns patti.

✖
Clear[{spec1,spec2,…}]

clears values and definitions for any symbols that are equal to or whose names match any of the speci.

Details

  • Clear does not clear attributes, defaults, options or messages associated with symbols. »
  • The pattern patt can be given as a string with metacharacters, as StringExpression[…] or as RegularExpression["regex"]. »
  • Clear allows abbreviated string patterns containing the following metacharacters:
  • *zero or more characters
    @one or more characters, excluding uppercase letters
  • Clear["context`*"] clears all symbols in a particular context. »
  • Clear["`*"] clears all symbols in the current context. »
  • Clear does not affect symbols with the attribute Protected. »
  • Clear has attribute HoldAll. »

Examples

open allclose all

Basic Examples  (2)Summary of the most common use cases

Clear a variable:

In[1]:=1
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https://wolfram.com/xid/0girdm-badhbb
In[2]:=2
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https://wolfram.com/xid/0girdm-q44gp

The variable no longer has a value:

In[3]:=3
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https://wolfram.com/xid/0girdm-k3zdk
Out[3]=3

Define values for a symbol:

In[1]:=1
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https://wolfram.com/xid/0girdm-sn84w8
In[2]:=2
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https://wolfram.com/xid/0girdm-lbffi1
Out[2]=2

Clear values:

In[3]:=3
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https://wolfram.com/xid/0girdm-qhk8ri
In[4]:=4
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https://wolfram.com/xid/0girdm-gds8wx
Out[4]=4

Scope  (12)Survey of the scope of standard use cases

Symbol Inputs  (7)

Clear values of variables (ownvalues):

In[1]:=1
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https://wolfram.com/xid/0girdm-cdnu4f
In[2]:=2
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https://wolfram.com/xid/0girdm-u5749k
Out[2]=2
In[3]:=3
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https://wolfram.com/xid/0girdm-c2li30
In[4]:=4
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https://wolfram.com/xid/0girdm-5u4ym
Out[4]=4

Clear functions (downvalues):

In[1]:=1
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https://wolfram.com/xid/0girdm-c9dse6
In[2]:=2
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https://wolfram.com/xid/0girdm-ltkigq
Out[2]=2
In[3]:=3
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https://wolfram.com/xid/0girdm-gfghut
In[4]:=4
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https://wolfram.com/xid/0girdm-1k5ot4
Out[4]=4

Clear upvalues:

In[1]:=1
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https://wolfram.com/xid/0girdm-gkvbc1
In[2]:=2
✖
https://wolfram.com/xid/0girdm-6g8nd2
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0girdm-dm4hnz
In[4]:=4
✖
https://wolfram.com/xid/0girdm-n06ifj
Out[4]=4

Clear subvalues:

In[1]:=1
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https://wolfram.com/xid/0girdm-fwskr0
In[2]:=2
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https://wolfram.com/xid/0girdm-hnjc85
Out[2]=2
In[3]:=3
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https://wolfram.com/xid/0girdm-uv4cc5
In[4]:=4
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https://wolfram.com/xid/0girdm-p9a816
Out[4]=4

Clear formatting:

In[1]:=1
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https://wolfram.com/xid/0girdm-vial91
In[2]:=2
✖
https://wolfram.com/xid/0girdm-xn9q7u
Out[2]=2
In[3]:=3
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https://wolfram.com/xid/0girdm-32e7wj
In[4]:=4
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https://wolfram.com/xid/0girdm-rtnqpj
Out[4]=4

Clear several symbols:

In[1]:=1
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https://wolfram.com/xid/0girdm-bp50b
In[2]:=2
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https://wolfram.com/xid/0girdm-tizdpb
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0girdm-m4f4ut
In[4]:=4
✖
https://wolfram.com/xid/0girdm-ch1vzf
Out[4]=4

Use a combination of symbols and symbol names:

In[1]:=1
✖
https://wolfram.com/xid/0girdm-2onlhh
In[2]:=2
✖
https://wolfram.com/xid/0girdm-e3odz5

Only x3 remains defined:

In[3]:=3
✖
https://wolfram.com/xid/0girdm-1f1k6s
Out[3]=3

Using Patterns  (5)

Specify symbols to clear as string patterns:

In[1]:=1
✖
https://wolfram.com/xid/0girdm-c2ufd6
In[2]:=2
✖
https://wolfram.com/xid/0girdm-d7ttq9
In[3]:=3
✖
https://wolfram.com/xid/0girdm-rysaf
Out[3]=3

Clear all symbols in the current context:

In[1]:=1
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https://wolfram.com/xid/0girdm-6slgzo
In[2]:=2
✖
https://wolfram.com/xid/0girdm-r70m2k
In[3]:=3
✖
https://wolfram.com/xid/0girdm-lgaxot
Out[3]=3

Clear all symbols in a given context:

In[1]:=1
✖
https://wolfram.com/xid/0girdm-wqeqjc
In[2]:=2
✖
https://wolfram.com/xid/0girdm-wzpzb
In[3]:=3
✖
https://wolfram.com/xid/0girdm-6wx1zi
Out[3]=3

Clear all 2-character symbols in the current context using StringExpression:

In[1]:=1
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https://wolfram.com/xid/0girdm-x7ppwu
In[2]:=2
✖
https://wolfram.com/xid/0girdm-0ghtad

The symbols x1 and x2 were cleared, but y remains unaffected:

In[3]:=3
✖
https://wolfram.com/xid/0girdm-zwe7vm
Out[3]=3

Clear all 3-character symbols in the current context using RegularExpression:

In[1]:=1
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https://wolfram.com/xid/0girdm-26w1um
In[2]:=2
✖
https://wolfram.com/xid/0girdm-ln5y9g
In[3]:=3
✖
https://wolfram.com/xid/0girdm-sxd17n
Out[3]=3

Applications  (2)Sample problems that can be solved with this function

Clear any old definitions before making new ones:

In[1]:=1
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https://wolfram.com/xid/0girdm-lanl90
In[2]:=2
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https://wolfram.com/xid/0girdm-o08r3d
In[4]:=4
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https://wolfram.com/xid/0girdm-p7j2an
Out[4]=4

Unprotect and clear all symbols in a package, to allow it to be read twice:

In[1]:=1
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https://wolfram.com/xid/0girdm-xyeurw
In[2]:=2
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https://wolfram.com/xid/0girdm-tkjxv3
In[3]:=3
✖
https://wolfram.com/xid/0girdm-1ogb5x
In[4]:=4
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https://wolfram.com/xid/0girdm-1eht7q
In[5]:=5
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https://wolfram.com/xid/0girdm-wsiohw

Properties & Relations  (6)Properties of the function, and connections to other functions

Clear[pattern] clears the same symbols as Clear/@Names[pattern]:

In[1]:=1
✖
https://wolfram.com/xid/0girdm-g68m9z
Out[3]=3
In[4]:=4
✖
https://wolfram.com/xid/0girdm-olxyis
Out[6]=6

Use Unset (=.) to clear definitions with a particular left-hand side:

In[1]:=1
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https://wolfram.com/xid/0girdm-mpj5jz
In[2]:=2
✖
https://wolfram.com/xid/0girdm-wqsuy
In[3]:=3
✖
https://wolfram.com/xid/0girdm-z4e5a
Out[3]=3

Clear all definitions:

In[4]:=4
✖
https://wolfram.com/xid/0girdm-dvfuo1
In[5]:=5
✖
https://wolfram.com/xid/0girdm-fjiqex
Out[5]=5

Clear does not remove attributes, defaults or options:

In[1]:=1
✖
https://wolfram.com/xid/0girdm-d9ifq8
In[2]:=2
✖
https://wolfram.com/xid/0girdm-i9a3c3
In[3]:=3
✖
https://wolfram.com/xid/0girdm-gbg3pw
Out[3]=3

Use ClearAll to clear everything:

In[4]:=4
✖
https://wolfram.com/xid/0girdm-fc1pz8
In[5]:=5
✖
https://wolfram.com/xid/0girdm-foikwx
Out[5]=5

Clear does not remove messages:

In[1]:=1
✖
https://wolfram.com/xid/0girdm-3r2fk5
In[2]:=2
✖
https://wolfram.com/xid/0girdm-1rtdik
In[3]:=3
✖
https://wolfram.com/xid/0girdm-fcys54

Use ClearAll to clear messages:

In[4]:=4
✖
https://wolfram.com/xid/0girdm-0lejh3
In[5]:=5
✖
https://wolfram.com/xid/0girdm-3t4ohc

Clear removes all definitions but leaves the symbol intact:

In[1]:=1
✖
https://wolfram.com/xid/0girdm-swru6m
In[2]:=2
✖
https://wolfram.com/xid/0girdm-1270ov
In[3]:=3
✖
https://wolfram.com/xid/0girdm-4mv80x
Out[3]=3

Remove removes the symbol completely:

In[4]:=4
✖
https://wolfram.com/xid/0girdm-bn6db5
In[5]:=5
✖
https://wolfram.com/xid/0girdm-topoov
Out[5]=5

Clear has the attribute HoldAll:

In[1]:=1
✖
https://wolfram.com/xid/0girdm-h5353g
Out[1]=1

This clears symbol itself:

In[2]:=2
✖
https://wolfram.com/xid/0girdm-fx3wr4
In[3]:=3
✖
https://wolfram.com/xid/0girdm-4d3chu
In[4]:=4
✖
https://wolfram.com/xid/0girdm-svaskv
Out[4]=4

This clears its value:

In[5]:=5
✖
https://wolfram.com/xid/0girdm-rc7lad
In[6]:=6
✖
https://wolfram.com/xid/0girdm-u2f10x
In[7]:=7
✖
https://wolfram.com/xid/0girdm-68t1mh
Out[7]=7

Possible Issues  (2)Common pitfalls and unexpected behavior

Protected symbols cannot be cleared:

In[1]:=1
✖
https://wolfram.com/xid/0girdm-f41vz7
In[3]:=3
✖
https://wolfram.com/xid/0girdm-npqgli

Use Unprotect to clear definitions of protected symbols:

In[4]:=4
✖
https://wolfram.com/xid/0girdm-csvxte

When using a pattern without a context mark, all matching symbols on $ContextPath are cleared:

In[1]:=1
✖
https://wolfram.com/xid/0girdm-yjoaby

The symbol xy was cleared, along with attempts to clear several system symbols:

In[2]:=2
✖
https://wolfram.com/xid/0girdm-fhjmtu
Out[2]=2

Use a pattern with an explicit context mark to avoid potentially matching symbols from system or other contexts:

In[3]:=3
✖
https://wolfram.com/xid/0girdm-8w4y3l
Wolfram Research (1988), Clear, Wolfram Language function, https://reference.wolfram.com/language/ref/Clear.html (updated 2022).
✖
Wolfram Research (1988), Clear, Wolfram Language function, https://reference.wolfram.com/language/ref/Clear.html (updated 2022).

Text

Wolfram Research (1988), Clear, Wolfram Language function, https://reference.wolfram.com/language/ref/Clear.html (updated 2022).

✖
Wolfram Research (1988), Clear, Wolfram Language function, https://reference.wolfram.com/language/ref/Clear.html (updated 2022).

CMS

Wolfram Language. 1988. "Clear." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2022. https://reference.wolfram.com/language/ref/Clear.html.

✖
Wolfram Language. 1988. "Clear." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2022. https://reference.wolfram.com/language/ref/Clear.html.

APA

Wolfram Language. (1988). Clear. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/Clear.html

✖
Wolfram Language. (1988). Clear. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/Clear.html

BibTeX

@misc{reference.wolfram_2025_clear, author="Wolfram Research", title="{Clear}", year="2022", howpublished="\url{https://reference.wolfram.com/language/ref/Clear.html}", note=[Accessed: 28-April-2025 ]}

✖
@misc{reference.wolfram_2025_clear, author="Wolfram Research", title="{Clear}", year="2022", howpublished="\url{https://reference.wolfram.com/language/ref/Clear.html}", note=[Accessed: 28-April-2025 ]}

BibLaTeX

@online{reference.wolfram_2025_clear, organization={Wolfram Research}, title={Clear}, year={2022}, url={https://reference.wolfram.com/language/ref/Clear.html}, note=[Accessed: 28-April-2025 ]}

✖
@online{reference.wolfram_2025_clear, organization={Wolfram Research}, title={Clear}, year={2022}, url={https://reference.wolfram.com/language/ref/Clear.html}, note=[Accessed: 28-April-2025 ]}