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ClearAll

✖
ClearAll[s1,s2,…]

clears all values, definitions, attributes, defaults, options and messages for the symbols si.

✖
ClearAll[patt1,patt2,…]

clears all symbols whose names textually match any of the arbitrary string patterns patti.

✖
ClearAll[{spec1,spec,…}]

clears any symbols that are equal to or whose names match any of the speci.

Details

Examples

open allclose all

Basic Examples  (1)Summary of the most common use cases

Define values and attributes for a symbol:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-b3tw6y
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-bal5sy
Out[3]=3

Clear values and attributes:

In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-liwpyn
In[5]:=5
✖
https://wolfram.com/xid/0tzqi180-hbyayt
Out[5]=5

Scope  (16)Survey of the scope of standard use cases

Symbol Inputs  (11)

Clear values of variables (ownvalues):

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-cdnu4f
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-escexy
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-c2li30
In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-5u4ym
Out[4]=4

Clear functions (downvalues):

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-c9dse6
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-ky6hnz
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-gfghut
In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-krgpda
Out[4]=4

Clear upvalues:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-gkvbc1
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-qq42u0
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-dm4hnz
In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-24p5o
Out[4]=4

Clear subvalues:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-dqc9p4
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-dh80v3
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-b23v3h
In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-u1j0yk
Out[4]=4

Clear formatting:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-vial91
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-xn9q7u
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-32e7wj
In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-rtnqpj
Out[4]=4

Clear attributes:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-xdfmrc
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-9l6r7t
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-v10pfi
In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-16z0x
Out[4]=4

Clear defaults:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-4rpya3
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-pp24va
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-xk94z7
In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-jyy4f6
Out[4]=4

Clear options:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-n9udql
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-6qoj1
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-fk54fc
In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-10oh4r
Out[4]=4

Clear messages:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-nfvdj9
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-o2sj45
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-7f4rj1
In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-wz920r

Clear several symbols:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-bp50b
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-9biq25
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-m4f4ut
In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-ch1vzf
Out[4]=4

Use a combination of symbols and symbol names:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-rxsim6
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-prz7px

Only x3 remains defined:

In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-rfj3a5
Out[3]=3

Using Patterns  (5)

Specify symbols to clear as string patterns:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-c2ufd6
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-d7ttq9
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-rysaf
Out[3]=3

Clear all symbols in the current context:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-6slgzo
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-r70m2k
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-lgaxot
Out[3]=3

Clear all symbols in a given context:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-wqeqjc
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-gc3xk2
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-6wx1zi
Out[3]=3

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

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-79mopk
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-jzfeke

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

In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-etkvxn
Out[3]=3

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

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-uheesw
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-ry5ruf
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-vhu5yu
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
✖
https://wolfram.com/xid/0tzqi180-lanl90
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-o08r3d
✖
https://wolfram.com/xid/0tzqi180-p7j2an
Out[4]=4

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

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-g66m9s
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-gc6puz
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-jkeqi5
In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-di9eh8
In[5]:=5
✖
https://wolfram.com/xid/0tzqi180-byveoq

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

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

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-g68m9z
Out[3]=3
In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-olxyis
Out[6]=6

Clear does not remove attributes, defaults or options:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-d9ifq8
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-szk4x2
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-2pzvt9
Out[3]=3

Use ClearAll to clear everything:

In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-fc1pz8
In[5]:=5
✖
https://wolfram.com/xid/0tzqi180-foikwx
Out[5]=5

Clear does not remove messages:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-3r2fk5
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-1rtdik
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-fcys54

Use ClearAll to clear messages:

In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-0lejh3
In[5]:=5
✖
https://wolfram.com/xid/0tzqi180-3t4ohc

ClearAll removes all properties and definitions but leaves the symbol intact:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-fo51hr
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-gw9s5s
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-9s7bx
Out[3]=3

Remove removes the symbol completely:

In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-2ttji2
In[5]:=5
✖
https://wolfram.com/xid/0tzqi180-qsshor
Out[5]=5

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

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-mpj5jz
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-wqsuy
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-z4e5a
Out[3]=3

Clear all definitions and properties:

In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-dvfuo1
In[5]:=5
✖
https://wolfram.com/xid/0tzqi180-fjiqex
Out[5]=5

ClearAll has the attribute HoldAll:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-fj68d5
Out[1]=1

This clears symbol itself:

In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-fx3wr4
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-q7exta
In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-svaskv
Out[4]=4

This clears its value:

In[5]:=5
✖
https://wolfram.com/xid/0tzqi180-4nh32l
In[6]:=6
✖
https://wolfram.com/xid/0tzqi180-mi3omu
In[7]:=7
✖
https://wolfram.com/xid/0tzqi180-i9ltzh
Out[7]=7

Possible Issues  (3)Common pitfalls and unexpected behavior

Protected symbols cannot be cleared:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-f41vz7
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-npqgli

Use Unprotect to clear definitions of protected symbols:

In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-csvxte

Clear can clear the values and definitions for locked symbols:

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-hu4t7s
In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-yxas0w
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-ceqn5b
In[4]:=4
✖
https://wolfram.com/xid/0tzqi180-3qij9n
Out[4]=4

ClearAll does not affect locked symbols:

In[5]:=5
✖
https://wolfram.com/xid/0tzqi180-ytpq5c
In[6]:=6
✖
https://wolfram.com/xid/0tzqi180-sc85rq
In[7]:=7
✖
https://wolfram.com/xid/0tzqi180-lyw8mz
Out[7]=7

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

In[1]:=1
✖
https://wolfram.com/xid/0tzqi180-yjoaby

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

In[2]:=2
✖
https://wolfram.com/xid/0tzqi180-fhjmtu
Out[2]=2

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

In[3]:=3
✖
https://wolfram.com/xid/0tzqi180-8w4y3l
Wolfram Research (1988), ClearAll, Wolfram Language function, https://reference.wolfram.com/language/ref/ClearAll.html (updated 2022).
✖
Wolfram Research (1988), ClearAll, Wolfram Language function, https://reference.wolfram.com/language/ref/ClearAll.html (updated 2022).

Text

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

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

CMS

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

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

APA

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

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

BibTeX

@misc{reference.wolfram_2025_clearall, author="Wolfram Research", title="{ClearAll}", year="2022", howpublished="\url{https://reference.wolfram.com/language/ref/ClearAll.html}", note=[Accessed: 11-July-2025 ]}

✖
@misc{reference.wolfram_2025_clearall, author="Wolfram Research", title="{ClearAll}", year="2022", howpublished="\url{https://reference.wolfram.com/language/ref/ClearAll.html}", note=[Accessed: 11-July-2025 ]}

BibLaTeX

@online{reference.wolfram_2025_clearall, organization={Wolfram Research}, title={ClearAll}, year={2022}, url={https://reference.wolfram.com/language/ref/ClearAll.html}, note=[Accessed: 11-July-2025 ]}

✖
@online{reference.wolfram_2025_clearall, organization={Wolfram Research}, title={ClearAll}, year={2022}, url={https://reference.wolfram.com/language/ref/ClearAll.html}, note=[Accessed: 11-July-2025 ]}