SymbolQ

Checks if an expression is a symbol, or not

ResourceFunction["SymbolQ"][expr]

gives True if expr is a symbol, and False otherwise.

Examples

Check if the expression is a symbol, or not:

In[1]:=

$ResourceFunction[ "https://www.wolframcloud.com/obj/arnoudb/DeployedResources/Function/\ SymbolQ"][x]$

Out[1]=

In[2]:=

$ResourceFunction[ "https://www.wolframcloud.com/obj/arnoudb/DeployedResources/Function/\ SymbolQ"][42]$

Out[2]=

In[3]:=

$ResourceFunction[ "https://www.wolframcloud.com/obj/arnoudb/DeployedResources/Function/\ SymbolQ"][f[x]]$

Out[3]=

SymbolQ does not evaluate its arguments:

In[4]:=

$ResourceFunction[ "https://www.wolframcloud.com/obj/arnoudb/DeployedResources/Function/\ SymbolQ"][$CloudBase]$

Out[4]=

In[5]:=

$ResourceFunction[ "https://www.wolframcloud.com/obj/arnoudb/DeployedResources/Function/\ SymbolQ"][a + a - a]$

Out[5]=

In[6]:=

$ResourceFunction[ "https://www.wolframcloud.com/obj/arnoudb/DeployedResources/Function/\ SymbolQ"][a]$

Out[6]=

SymbolQ can be used with Select:

In[7]:=

$Select[{1, 4.2, f[x], x}, ResourceFunction[ "https://www.wolframcloud.com/obj/arnoudb/DeployedResources/Function/\ SymbolQ"]]$

Out[7]=