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AtomQ

Status: Stable

documented, exercised by the test suite and/or worked examples, with no known limitations recorded.

Description

AtomQ[expr]
    gives True if expr is an atomic object (Integer, Real, BigInt,
    Rational, Complex, Symbol, or String), and False if expr is a
    compound expression of the form head[...].

Examples

All examples below are verified against the current Mathilda build.

In[1]:= MachineNumberQ[Sin[1000.]]
Out[1]= True

In[2]:= MachineNumberQ[Exp[1000.]]      (* overflows to +inf *)
Out[2]= False

In[3]:= MachineNumberQ[-29037945.290347]
Out[3]= True

In[4]:= MachineNumberQ[N[Pi, 30]]       (* MPFR, not machine *)
Out[4]= False

In[5]:= MachineNumberQ[1.0 + 2.0 I]
Out[5]= True

In[6]:= MachineNumberQ[1 + 2 I]         (* exact Gaussian integer *)
Out[6]= False

Implementation notes

builtin_atomq (src/core.c) returns True for any non-EXPR_FUNCTION node (integers, reals, bigints, symbols, strings) and for the two function heads Mathilda treats as atomic, Rational and Complex; every other EXPR_FUNCTION yields False.

Attributes: Protected.

Implementation status

Stable — documented, exercised by the test suite and/or worked examples, with no known limitations recorded.

References