就像数值向量一样，我们可以找到两个字符串向量之间存在的不同元素。为此，我们可以使用setdiff函数。例如，如果我们有一个向量V1包含a，b，c，d，e，f，而另一个向量V2包含a，e，h，k，l，p，r，u，v，w，则这两个向量之间的不同元素可以找到为setdiff(V1,V2)。
x1<-LETTERS[1:26] x1
输出结果
[1] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" "K" "L" "M" "N" "O" "P" "Q" "R" "S" [20] "T" "U" "V" "W" "X" "Y" "Z"
x2<-LETTERS[5:21] x2
输出结果
[1] "E" "F" "G" "H" "I" "J" "K" "L" "M" "N" "O" "P" "Q" "R" "S" "T" "U" setdiff(x1,x2) [1] "A" "B" "C" "D" "V" "W" "X" "Y" "Z"
x3<-c("Alabama", "Alaska", "American Samoa", "Arizona", "Arkansas", "California", "Colorado", "Connecticut", "Delaware", "District of Columbia", "Florida", "Georgia", "Guam", "Hawaii", "Idaho", "Illinois", "Indiana", "Iowa", "Kansas", "Kentucky", "Louisiana", "Maine", "Maryland", "Massachusetts", "Michigan", "Minnesota", "Minor Outlying Islands", "Mississippi", "Missouri", "Montana", "Nebraska", "Nevada", "New Hampshire", "New Jersey", "New Mexico", "New York", "North Carolina", "North Dakota", "Northern Mariana Islands", "Ohio", "Oklahoma", "Oregon", "Pennsylvania", "Puerto Rico", "Rhode Island", "South Carolina", "South Dakota", "Tennessee", "Texas", "U.S. Virgin Islands", "Utah", "Vermont", "Virginia", "Washington", "West Virginia", "Wisconsin", "Wyoming")
x3输出结果
[1] "Alabama" "Alaska" [3] "American Samoa" "Arizona" [5] "Arkansas" "California" [7] "Colorado" "Connecticut" [9] "Delaware" "District of Columbia" [11] "Florida" "Georgia" [13] "Guam" "Hawaii" [15] "Idaho" "Illinois" [17] "Indiana" "Iowa" [19] "Kansas" "Kentucky" [21] "Louisiana" "Maine" [23] "Maryland" "Massachusetts" [25] "Michigan" "Minnesota" [27] "Minor Outlying Islands" "Mississippi" [29] "Missouri" "Montana" [31] "Nebraska" "Nevada" [33] "New Hampshire" "New Jersey" [35] "New Mexico" "New York" [37] "North Carolina" "North Dakota" [39] "Northern Mariana Islands" "Ohio" [41] "Oklahoma" "Oregon" [43] "Pennsylvania" "Puerto Rico" [45] "Rhode Island" "South Carolina" [47] "South Dakota" "Tennessee" [49] "Texas" "U.S. Virgin Islands" [51] "Utah" "Vermont" [53] "Virginia" "Washington" [55] "West Virginia" "Wisconsin" [57] "Wyoming"
x4<-c("Alabama", "Alaska", "American Samoa", "Arizona", "Arkansas", "California","Florida", "Georgia", "Guam", "Hawaii", "Idaho", "Louisiana", "Maine", "Maryland", "Mississippi", "Missouri", "New Jersey", "New Mexico", "New York", "North Carolina", "Puerto Rico", "Rhode Island", "South Carolina", "South Dakota", "Tennessee")
x4输出结果
[1] "Alabama" "Alaska" "American Samoa" "Arizona" [5] "Arkansas" "California" "Florida" "Georgia" [9] "Guam" "Hawaii" "Idaho" "Louisiana" [13] "Maine" "Maryland" "Mississippi" "Missouri" [17] "New Jersey" "New Mexico" "New York" "North Carolina" [21] "Puerto Rico" "Rhode Island" "South Carolina" "South Dakota" [25] "Tennessee" setdiff(x3,x4) [1] "Colorado" "Connecticut" [3] "Delaware" "District of Columbia" [5] "Illinois" "Indiana" [7] "Iowa" "Kansas" [9] "Kentucky" "Massachusetts" [11] "Michigan" "Minnesota" [13] "Minor Outlying Islands" "Montana" [15] "Nebraska" "Nevada" [17] "New Hampshire" "North Dakota" [19] "Northern Mariana Islands" "Ohio" [21] "Oklahoma" "Oregon" [23] "Pennsylvania" "Texas" [25] "U.S. Virgin Islands" "Utah" [27] "Vermont" "Virginia" [29] "Washington" "West Virginia" [31] "Wisconsin" "Wyoming"
x5<-c("AK", "AL", "AR", "AS", "AZ", "CA", "CO", "CT", "DC", "DE", "FL", "GA", "GU", "HI", "IA", "ID", "IL", "IN", "KS", "KY", "LA", "MA", "MD", "ME", "MI", "MN", "MO", "MP", "MS", "MT", "NC", "ND", "NE", "NH", "NJ", "NM", "NV", "NY", "OH", "OK", "OR", "PA", "PR", "RI", "SC", "SD", "TN", "TX", "UM", "UT", "VA", "VI", "VT", "WA", "WI", "WV", "WY")
x5输出结果
[1] "AK" "AL" "AR" "AS" "AZ" "CA" "CO" "CT" "DC" "DE" "FL" "GA" "GU" "HI" "IA" [16] "ID" "IL" "IN" "KS" "KY" "LA" "MA" "MD" "ME" "MI" "MN" "MO" "MP" "MS" "MT" [31] "NC" "ND" "NE" "NH" "NJ" "NM" "NV" "NY" "OH" "OK" "OR" "PA" "PR" "RI" "SC" [46] "SD" "TN" "TX" "UM" "UT" "VA" "VI" "VT" "WA" "WI" "WV" "WY"
x6<-c("AK", "CA", "CO", "CT", "HI", "IA", "ID", "IL", "MD", "ME", "MI", "MN", "MO", "MP", "MS", "MT", "NC", "ND", "NE", "NH", "OR", "PA", "PR", "RI", "SC")
x6输出结果
[1] "AK" "CA" "CO" "CT" "HI" "IA" "ID" "IL" "MD" "ME" "MI" "MN" "MO" "MP" "MS" [16] "MT" "NC" "ND" "NE" "NH" "OR" "PA" "PR" "RI" "SC"