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

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_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.

Implementation status

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

References