head(USArrests)
# 1.获取各州的简称
states = rownames(USArrests);head(states) #获取州的名字集合
abbreviate(states,minlength = 5)

# 2.统计最长的州名
state_chars <- nchar(states);head(state_chars)#获取每个州名的字母数量
states[which(state_chars == max(state_chars))]#名字最长的州

# 3.获取含有特定字符“New”、"South"的州名
grep(pattern = "New",x = states,value = TRUE) #获取含有“NEW”的州名
grep(pattern = "South",x = states,value = TRUE) #获取含有“South”的州名

# 4.将所有的州名中的"n"都转换成大写
gsub('[n]','N',states)