Define a function or symbol

Define a function f:

In[1]:=1

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Find the definition of a function or symbol

Find the definition of f:

In[2]:=2

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Out[2]=2

• You can also use Definition to get a symbol or a function’s definition.

Clear the definition of a function or symbol

Clear the definition of f:

In[3]:=3

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The function f is no longer defined:

In[4]:=4

✖

Out[4]=4

Notes

If you redefine a function, using Clear beforehand will ensure that no unwanted definitions linger and cause potential problems.

Symbols whose values are assigned with Set (e.g. ) can be cleared with Unset (e.g. ).

Clear clears definitions, but not attributes, messages or defaults associated with symbols. Use ClearAll to clear all information associated with a symbol.

Clear and ClearAll leave the cleared symbol intact. Use Remove to remove the symbol completely:

In[5]:=5

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Out[5]=5

In[6]:=6

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The symbol x persists after Clear:

In[7]:=7

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Out[7]=7

Remove the symbol completely:

In[8]:=8

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In[9]:=9

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Out[9]=9