WOLFRAM

Wolfram Language & System Documentation Center

x*=c

multiplies x by c and returns the new value of x.

Details
Details and Options Details and Options
Examples  
Basic Examples  
Scope  
Applications  
Properties & Relations  
Possible Issues  
See Also
Tech Notes
Related Guides
History
Cite this Page

TimesBy

x*=c

multiplies x by c and returns the new value of x.

Details

  • x*=c is equivalent to x=x*c.
  • TimesBy has the attribute HoldFirst.
  • In TimesBy[x,c], x can be a symbol or other expression with an existing value. »

Examples

open all close all

Basic Examples  (1)

Wolfram Language code: k = 3; k *= 5
Wolfram Language code: k

Scope  (4)

Multiply by a numerical value:

Wolfram Language code: x = 1.5; x *= 2.5;x

Multiply by a symbolic value:

Wolfram Language code: v = a;v *= b;v

Multiply all values in a list by a scalar:

Wolfram Language code: x = {1, 2, 3}
Wolfram Language code: x *= 2;x

Multiply all values in a list by another list:

Wolfram Language code: x *= {10, 20, 30};x

The first argument to TimesBy need not be a symbol:

Wolfram Language code: list = {1, 2, 3}
Wolfram Language code: list[[2]] *= c
Wolfram Language code: list

Applications  (1)

Find the first power of two above one million:

Wolfram Language code: i = 1; While[i < 10 ^ 6, i *= 2];i

Properties & Relations  (2)

TimesBy is a short form of this assignment:

Wolfram Language code: k = 1; k = k * 2

DivideBy is closely related:

Wolfram Language code: k = 2; k *= 2
Wolfram Language code: k /= 2

Possible Issues  (1)

A variable to be multiplied must have an initial value:

Wolfram Language code: x *= 2
Wolfram Research (1988), TimesBy, Wolfram Language function, https://reference.wolfram.com/language/ref/TimesBy.html.

Text

Wolfram Research (1988), TimesBy, Wolfram Language function, https://reference.wolfram.com/language/ref/TimesBy.html.

CMS

Wolfram Language. 1988. "TimesBy." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/TimesBy.html.

APA

Wolfram Language. (1988). TimesBy. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/TimesBy.html

BibTeX

@misc{reference.wolfram_2026_timesby, author="Wolfram Research", title="{TimesBy}", year="1988", howpublished="\url{https://reference.wolfram.com/language/ref/TimesBy.html}", note=[Accessed: 13-June-2026]}

BibLaTeX

@online{reference.wolfram_2026_timesby, organization={Wolfram Research}, title={TimesBy}, year={1988}, url={https://reference.wolfram.com/language/ref/TimesBy.html}, note=[Accessed: 13-June-2026]}