RealValuedNumericQ

RealValuedNumericQ[expr]

gives True if expr is a real-valued numeric quantity, and False otherwise.

Details

Examples

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Basic Examples  (2)

RealValuedNumericQ tests whether an object is a real-valued numeric quantity:

RealValuedNumericQ[expr] gives True whenever N[expr] yields a number with head Real:

A general symbolic expression is not a real-valued numeric quantity:

Scope  (9)

Integers and rationals are real-valued numeric quantities:

Approximate reals are real-valued numeric quantities:

RealValuedNumericQ gives True for real-valued mathematical constants:

RealValuedNumericQ gives True for exact expressions representing real values:

Complex numbers are not real-valued quantities:

Exact complex quantities whose imaginary part is zero are real valued:

The number has a real part of and an imaginary part of :

Approximate complex numbers are not considered real valued even if their imaginary part equals zero:

RealValuedNumericQ[Infinity] gives False:

RealValuedNumericQ[Overflow[]] and RealValuedNumericQ[Underflow[]] give True:

They are both treated as Real:

Properties & Relations  (3)

If Head[N[x]] is Real, then RealValuedNumericQ[x] is True:

It is possible for RealValuedNumericQ[x] to be True and for N[x] to have head Complex:

This indicates that x has an imaginary part that is exactly zero:

If RealValuedNumberQ[x] is True, then RealValuedNumericQ[x] is also True:

Possible Issues  (2)

Exact quantities whose imaginary parts vanish may not be identified by RealValuedNumericQ:

If detecting such numbers is important, simplify the expression before testing it:

An exact number and its numerical approximation may give different results for RealValuedNumericQ:

It is not possible to determine if the number is real, as its imaginary part is only approximately zero:

Wolfram Research (2023), RealValuedNumericQ, Wolfram Language function, https://reference.wolfram.com/language/ref/RealValuedNumericQ.html.

Text

Wolfram Research (2023), RealValuedNumericQ, Wolfram Language function, https://reference.wolfram.com/language/ref/RealValuedNumericQ.html.

CMS

Wolfram Language. 2023. "RealValuedNumericQ." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/RealValuedNumericQ.html.

APA

Wolfram Language. (2023). RealValuedNumericQ. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/RealValuedNumericQ.html

BibTeX

@misc{reference.wolfram_2024_realvaluednumericq, author="Wolfram Research", title="{RealValuedNumericQ}", year="2023", howpublished="\url{https://reference.wolfram.com/language/ref/RealValuedNumericQ.html}", note=[Accessed: 22-July-2024 ]}

BibLaTeX

@online{reference.wolfram_2024_realvaluednumericq, organization={Wolfram Research}, title={RealValuedNumericQ}, year={2023}, url={https://reference.wolfram.com/language/ref/RealValuedNumericQ.html}, note=[Accessed: 22-July-2024 ]}