AtomQ
AtomQ(x)
is true if
x
is an atom (an object such as a number or string, which cannot be divided into subexpressions using ‘Part’).
Examples
>> AtomQ(x)True
>> AtomQ(1.2)True
>> AtomQ(2 + I)True
>> AtomQ(2 / 3)True
>> AtomQ(x + y)False