Real-valued function
（重定向自Real valued function）
![Mass measured in grams is a function from this collection of weight to positive real numbers. The term](/Images/godic/202502/06/Weights_20mg~500g0729.jpg")
In mathematics, a real-valued function or real function is a function whose values are real numbers. In other words, it is a function that assigns a real number to each member of its domain.
Many important function spaces are defined to consist of real functions.