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IntegerQ

Status: Stable

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

Description

IntegerQ[expr]

gives True if expr is an Integer or BigInt, False otherwise.

Notes Returns False on rationals with denominator \> 1, reals, and symbolic expressions (even those that are integer-valued, e.g. 2 Pi / Pi).

Examples (10)

Every input below was run against the current Mathilda build and its output recorded.

Basic examples (4)

In[1]:= StringQ["AbC"]
Out[1]= True

In[2]:= StringQ[""]
Out[2]= True

In[3]:= StringQ[123]
Out[3]= False

In[4]:= StringQ[] StringQ::argx: StringQ called with 0 arguments; 1 argument is expected.

Scope (6)

In[5]:= MachineNumberQ[Sin[1000.]]
Out[5]= True

Overflows to +inf

In[6]:= MachineNumberQ[Exp[1000.]]
Out[6]= False

In[7]:= MachineNumberQ[-29037945.290347]
Out[7]= True

MPFR, not machine

In[8]:= MachineNumberQ[N[Pi, 30]]
Out[8]= False

In[9]:= MachineNumberQ[1.0 + 2.0 I]
Out[9]= True

Exact Gaussian integer

In[10]:= MachineNumberQ[1 + 2 I]
Out[10]= False

Implementation notes

builtin_integerq (src/core.c) returns True exactly when expr_is_integer_like(arg) holds (an EXPR_INTEGER or EXPR_BIGINT), and False otherwise.

Attributes: Protected.

References

See also: AtomQ, NumberQ, StringQ, MachineNumberQ, Complex, ExactNumberQ