求最大值，最小值，平均值，中值。

Code :

> library(plyr)

> x<-rnorm(50)

>each(max,min,mean,median,sd)(x)

       max         min        mean      median          sd

 1.88221163 -1.52919038  0.01542068 -0.01443496  0.80924832

> x

 [1] -0.03896171  1.05968843 0.60683138  0.79635301 -0.28065734-0.14786892

 [7] -0.95131844  0.38734777 1.88221163 -0.07776889 -0.37887712 1.05016316

[13] -0.65355046  0.28679027 -1.07974448  0.48795803 0.77793701 -0.66422108

[19] -0.94495008 -0.50267731  0.26920767 -0.11112345  1.49338686 -1.38668512

[25]  0.71392881 0.07792029 -0.42848838 0.39862112  0.01009179 -1.32298277

[31]  0.41386912 0.92087498  0.52594607  0.46603867 -0.35325559 -1.25671916

[37] -0.21924526 -0.32232343  1.28370409 1.13865978  1.07994270 -0.28619480

[43]  0.22691893 -0.58377522 -1.52919038  0.27830182 -0.87762173  0.41305739

[49] -0.94360299 -0.93291290