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# ´ÓirisÀïÄóöÒ»²¿·ÖÊý¾Ý(Ç°ÁùÐÐÒÔ¼°Ç°ËÄÁÐ)½øÐÐÑÝʾ
test<- iris[1:6,1:4];test

##   Sepal.Length Sepal.Width Petal.Length Petal.Width
## 1          5.1         3.5          1.4         0.2
## 2          4.9         3.0          1.4         0.2
## 3          4.7         3.2          1.3         0.2
## 4          4.6         3.1          1.5         0.2
## 5          5.0         3.6          1.4         0.2
## 6          5.4         3.9          1.7         0.4

class(test)

## [1] "data.frame"

apply(test,2,mean) # ¼ÆËãÿһÁеÄƽ¾ùÖµ

## Sepal.Length  Sepal.Width Petal.Length  Petal.Width 
##    4.9500000    3.3833333    1.4500000    0.2333333

apply(test,1,sum)  # ¼ÆËãÿһÐеÄÇóºÍ

##    1    2    3    4    5    6 
## 10.2  9.5  9.4  9.4 10.2 11.4

# ÓõIJ»¶à¾Í²»Ï¸ËµÁË
lapply(1:4,rnorm) # 1:4ÊÇÖ¸ÓÉ1¡¢2¡¢3¡¢4ËĸöÊý×Ö×é³ÉµÄÏòÁ¿£¬ºóÃæÄǸöÊǺ¯Êý

## [[1]]
## [1] 0.7631465
## 
## [[2]]
## [1]  0.7791411 -0.7520658
## 
## [[3]]
## [1] -1.0453939  0.5303851 -2.3555369
## 
## [[4]]
## [1] -1.4277072  1.7687711  0.5577922 -0.4110200