什么是函数？
R 金融中级
Lore Dirick
Manager of Data Science Curriculum at Flatiron School
函数文档
?matrix
函数参数示例
returns <- c(.023, .044, .034, NA)mean()
Error in mean.default() : argument "x" is missing, with no default
mean(returns)
NA
?mean
mean(returns, na.rm = TRUE)
0.03366667
