有时，字符串向量中的值的末尾有多余的空格，这可能在键入值时或由于其他一些手动错误而发生。要删除字符串向量末尾的空格，我们可以使用gsub函数。例如，如果我们有一个名为x的向量，该向量的末尾包含带空格的字符串值，则可以通过使用命令gsub（“ $”，“”，x，perl = T）来删除值。
x1<-sample(c("india ","croatia ","egypt "),100,replace=TRUE)
x1输出结果[1] "croatia " "india " "india " "india " "croatia " "india " [7] "india " "egypt " "croatia " "egypt " "croatia " "croatia " [13] "croatia " "croatia " "croatia " "croatia " "india " "egypt " [19] "india " "croatia " "croatia " "croatia " "croatia " "croatia " [25] "croatia " "croatia " "india " "india " "egypt " "croatia " [31] "india " "croatia " "egypt " "egypt " "croatia " "croatia " [37] "croatia " "croatia " "croatia " "india " "croatia " "croatia " [43] "croatia " "egypt " "india " "india " "india " "croatia " [49] "egypt " "egypt " "croatia " "croatia " "croatia " "egypt " [55] "egypt " "india " "egypt " "egypt " "egypt " "egypt " [61] "croatia " "india " "egypt " "india " "india " "croatia " [67] "india " "egypt " "croatia " "india " "egypt " "egypt " [73] "croatia " "egypt " "india " "india " "croatia " "egypt " [79] "egypt " "india " "egypt " "croatia " "egypt " "india " [85] "croatia " "india " "india " "india " "india " "india " [91] "croatia " "croatia " "egypt " "egypt " "india " "egypt " [97] "egypt " "croatia " "croatia " "croatia "
x1<-gsub(" $","",x1,perl=T)
x1输出结果[1] "croatia" "india" "india" "india" "croatia" "india" "india" [8] "egypt" "croatia" "egypt" "croatia" "croatia" "croatia" "croatia" [15] "croatia" "croatia" "india" "egypt" "india" "croatia" "croatia" [22] "croatia" "croatia" "croatia" "croatia" "croatia" "india" "india" [29] "egypt" "croatia" "india" "croatia" "egypt" "egypt" "croatia" [36] "croatia" "croatia" "croatia" "croatia" "india" "croatia" "croatia" [43] "croatia" "egypt" "india" "india" "india" "croatia" "egypt" [50] "egypt" "croatia" "croatia" "croatia" "egypt" "egypt" "india" [57] "egypt" "egypt" "egypt" "egypt" "croatia" "india" "egypt" [64] "india" "india" "croatia" "india" "egypt" "croatia" "india" [71] "egypt" "egypt" "croatia" "egypt" "india" "india" "croatia" [78] "egypt" "egypt" "india" "egypt" "croatia" "egypt" "india" [85] "croatia" "india" "india" "india" "india" "india" "croatia" [92] "croatia" "egypt" "egypt" "india" "egypt" "egypt" "croatia" [99] "croatia" "croatia"
x2<-sample(c("male ","female "),100,replace=TRUE)
x2输出结果[1] "female " "female " "male " "male " "male " "female " "male " [8] "female " "female " "male " "male " "male " "female " "male " [15] "male " "female " "female " "female " "male " "male " "male " [22] "female " "female " "male " "female " "male " "female " "male " [29] "female " "female " "female " "male " "male " "female " "female " [36] "male " "male " "female " "female " "male " "female " "male " [43] "male " "male " "male " "male " "male " "female " "male " [50] "female " "male " "female " "male " "female " "male " "male " [57] "male " "female " "male " "female " "female " "male " "female " [64] "male " "male " "male " "female " "female " "male " "female " [71] "female " "female " "female " "female " "male " "female " "male " [78] "female " "male " "female " "male " "male " "male " "female " [85] "male " "female " "male " "male " "female " "male " "male " [92] "female " "male " "female " "male " "male " "female " "male " [99] "male " "male "
x2<-gsub(" $","",x2,perl=T)
x2输出结果[1] "female" "female" "male" "male" "male" "female" "male" "female" [9] "female" "male" "male" "male" "female" "male" "male" "female" [17] "female" "female" "male" "male" "male" "female" "female" "male" [25] "female" "male" "female" "male" "female" "female" "female" "male" [33] "male" "female" "female" "male" "male" "female" "female" "male" [41] "female" "male" "male" "male" "male" "male" "male" "female" [49] "male" "female" "male" "female" "male" "female" "male" "male" [57] "male" "female" "male" "female" "female" "male" "female" "male" [65] "male" "male" "female" "female" "male" "female" "female" "female" [73] "female" "female" "male" "female" "male" "female" "male" "female" [81] "male" "male" "male" "female" "male" "female" "male" "male" [89] "female" "male" "male" "female" "male" "female" "male" "male" [97] "female" "male" "male" "male"
x3<-sample(c("hot ","cold ","warm "),100,replace=TRUE)
x3输出结果[1] "cold " "hot " "hot " "warm " "hot " "hot " "hot " "hot " "hot " [10] "hot " "hot " "cold " "hot " "cold " "cold " "cold " "hot " "cold " [19] "cold " "cold " "cold " "cold " "cold " "hot " "warm " "warm " "hot " [28] "warm " "hot " "hot " "hot " "warm " "cold " "cold " "cold " "hot " [37] "warm " "cold " "hot " "cold " "hot " "cold " "cold " "cold " "hot " [46] "cold " "warm " "cold " "warm " "cold " "warm " "cold " "warm " "warm " [55] "cold " "hot " "cold " "warm " "warm " "cold " "cold " "cold " "hot " [64] "warm " "cold " "hot " "cold " "cold " "warm " "warm " "hot " "warm " [73] "cold " "warm " "cold " "warm " "hot " "warm " "cold " "hot " "hot " [82] "cold " "warm " "cold " "cold " "hot " "cold " "hot " "hot " "cold " [91] "cold " "hot " "cold " "cold " "cold " "warm " "hot " "warm " "cold " [100] "hot "
x3<-gsub(" $","",x3,perl=T)
x3输出结果[1] "cold" "hot" "hot" "warm" "hot" "hot" "hot" "hot" "hot" "hot" [11] "hot" "cold" "hot" "cold" "cold" "cold" "hot" "cold" "cold" "cold" [21] "cold" "cold" "cold" "hot" "warm" "warm" "hot" "warm" "hot" "hot" [31] "hot" "warm" "cold" "cold" "cold" "hot" "warm" "cold" "hot" "cold" [41] "hot" "cold" "cold" "cold" "hot" "cold" "warm" "cold" "warm" "cold" [51] "warm" "cold" "warm" "warm" "cold" "hot" "cold" "warm" "warm" "cold" [61] "cold" "cold" "hot" "warm" "cold" "hot" "cold" "cold" "warm" "warm" [71] "hot" "warm" "cold" "warm" "cold" "warm" "hot" "warm" "cold" "hot" [81] "hot" "cold" "warm" "cold" "cold" "hot" "cold" "hot" "hot" "cold" [91] "cold" "hot" "cold" "cold" "cold" "warm" "hot" "warm" "cold" "hot"
x4<-sample(c("Asia ","America ","Africa ","Europe ","Oceania "),100,replace=TRUE)
x4输出结果[1] "Europe " "Europe " "Oceania " "America " "Africa " "Europe " [7] "America " "Asia " "Europe " "Africa " "Asia " "Asia " [13] "Oceania " "Asia " "Oceania " "Europe " "Europe " "America " [19] "Oceania " "Europe " "Asia " "Europe " "Europe " "America " [25] "Asia " "Asia " "Oceania " "Africa " "Oceania " "Asia " [31] "Africa " "Africa " "Oceania " "Oceania " "Oceania " "Africa " [37] "Africa " "Africa " "America " "America " "Asia " "Africa " [43] "Africa " "Oceania " "Asia " "Oceania " "Europe " "Europe " [49] "Asia " "Oceania " "Africa " "America " "Europe " "Europe " [55] "Europe " "Asia " "Europe " "Oceania " "Oceania " "Oceania " [61] "Oceania " "Europe " "Oceania " "America " "Europe " "America " [67] "America " "Europe " "Europe " "Africa " "Asia " "Asia " [73] "Asia " "Europe " "America " "Europe " "America " "Oceania " [79] "Europe " "Africa " "Asia " "America " "Asia " "America " [85] "Europe " "Europe " "Oceania " "Europe " "Asia " "America " [91] "Asia " "Asia " "Oceania " "Oceania " "Asia " "Asia " [97] "Asia " "Asia " "Europe " "Oceania "
x4<-gsub(" $","",x4,perl=T)
x4输出结果[1] "Europe" "Europe" "Oceania" "America" "Africa" "Europe" "America" [8] "Asia" "Europe" "Africa" "Asia" "Asia" "Oceania" "Asia" [15] "Oceania" "Europe" "Europe" "America" "Oceania" "Europe" "Asia" [22] "Europe" "Europe" "America" "Asia" "Asia" "Oceania" "Africa" [29] "Oceania" "Asia" "Africa" "Africa" "Oceania" "Oceania" "Oceania" [36] "Africa" "Africa" "Africa" "America" "America" "Asia" "Africa" [43] "Africa" "Oceania" "Asia" "Oceania" "Europe" "Europe" "Asia" [50] "Oceania" "Africa" "America" "Europe" "Europe" "Europe" "Asia" [57] "Europe" "Oceania" "Oceania" "Oceania" "Oceania" "Europe" "Oceania" [64] "America" "Europe" "America" "America" "Europe" "Europe" "Africa" [71] "Asia" "Asia" "Asia" "Europe" "America" "Europe" "America" [78] "Oceania" "Europe" "Africa" "Asia" "America" "Asia" "America" [85] "Europe" "Europe" "Oceania" "Europe" "Asia" "America" "Asia" [92] "Asia" "Oceania" "Oceania" "Asia" "Asia" "Asia" "Asia" [99] "Europe" "Oceania"