有时，字符串向量在结尾或开头包含不必要的字符并且没有意义，也有可能使字符串有意义，但也不要求存在拼写错误。在这种情况下，我们需要删除不必要的字符。这可以通过使用gsub函数来完成。
x1<−"Nhooo is an E-learning website and one of the biggest websites in the worlds"
gsub('.{1}$','',x1)输出结果[1] "Nhooo is an E-learning website and one of the biggest websites in the world"
x2<−c("Alabamaa", "Alaskaa", "American Samoaa", "Arizonaa", "Arkansass", "Californiaa", "Coloradoo", "Connecticutt", "Delawaree", "District of Columbiaa", "Floridaa", "Georgiaa", "Guamm", "Hawaiii", "Idahoo", "Illinoiss", "Indianaa", "Iowaa", "Kansass", "Kentuckyy", "Louisianaa", "Mainee", "Marylandd", "Massachusettss", "Michigann", "Minnesotaa", "Minor Outlying Islandss", "Mississippii", "Missourii", "Montanaa", "Nebraskaa", "Nevadaa", "New Hampshiree", "New Jerseyy", "New Mexicoo", "New Yorkk", "North Carolinaa", "North Dakotaa", "Northern Mariana Islandss", "Ohioo", "Oklahomaa", "Oregonn", "Pennsylvaniaa", "Puerto Ricoo", "Rhode Islandd", "South Carolinaa", "South Dakotaa", "Tennesseee", "Texasx", "U.S. Virgin Islandss", "Utahh", "Vermontt", "Virginiaa", "Washingtonn", "West Virginiaa", "Wisconsinn", "Wyomingg")
x2输出结果[1] "Alabamaa" "Alaskaa" [3] "American Samoaa" "Arizonaa" [5] "Arkansass" "Californiaa" [7] "Coloradoo" "Connecticutt" [9] "Delawaree" "District of Columbiaa" [11] "Floridaa" "Georgiaa" [13] "Guamm" "Hawaiii" [15] "Idahoo" "Illinoiss" [17] "Indianaa" "Iowaa" [19] "Kansass" "Kentuckyy" [21] "Louisianaa" "Mainee" [23] "Marylandd" "Massachusettss" [25] "Michigann" "Minnesotaa" [27] "Minor Outlying Islandss" "Mississippii" [29] "Missourii" "Montanaa" [31] "Nebraskaa" "Nevadaa" [33] "New Hampshiree" "New Jerseyy" [35] "New Mexicoo" "New Yorkk" [37] "North Carolinaa" "North Dakotaa" [39] "Northern Mariana Islandss" "Ohioo" [41] "Oklahomaa" "Oregonn" [43] "Pennsylvaniaa" "Puerto Ricoo" [45] "Rhode Islandd" "South Carolinaa" [47] "South Dakotaa" "Tennesseee" [49] "Texasx" "U.S. Virgin Islandss" [51] "Utahh" "Vermontt" [53] "Virginiaa" "Washingtonn" [55] "West Virginiaa" "Wisconsinn" [57] "Wyomingg"
gsub('.{1}$','',x2)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"
x3<−c("AKK", "ALL", "ARR", "ASS", "AZZ", "CAA", "COO", "CTT", "DCC", "DEE", "FFLL", "GAA", "GUU", "HII", "IAA", "IDD", "ILL", "INN", "KSS", "KYY", "LAA", "MAA", "MDD", "MEE", "MII", "MNN", "MOO", "MPP", "MSS", "MTT", "NCC", "NDD", "NEE", "NHH", "NJJ", "NMM", "NVV", "NYY", "OHH", "OKK", "ORR", "PAA", "PRR", "RII", "SCC", "SDD", "TNN", "TXX", "UMM", "UTT", "VAA", "VII", "VTT", "WAA", "WII", "WVV", "WYY")
x3
[1] "AKK" "ALL" "ARR" "ASS" "AZZ" "CAA" "COO" "CTT" "DCC" "DEE"
[11] "FFLL" "GAA" "GUU" "HII" "IAA" "IDD" "ILL" "INN" "KSS" "KYY"
[21] "LAA" "MAA" "MDD" "MEE" "MII" "MNN" "MOO" "MPP" "MSS" "MTT"
[31] "NCC" "NDD" "NEE" "NHH" "NJJ" "NMM" "NVV" "NYY" "OHH" "OKK"
[41] "ORR" "PAA" "PRR" "RII" "SCC" "SDD" "TNN" "TXX" "UMM" "UTT"
[51] "VAA" "VII" "VTT" "WAA" "WII" "WVV" "WYY"
gsub('.{1}$','',x3)
[1] "AK" "AL" "AR" "AS" "AZ" "CA" "CO" "CT" "DC" "DE" "FFL" "GA"
[13] "GU" "HI" "IA" "ID" "IL" "IN" "KS" "KY" "LA" "MA" "MD" "ME"
[25] "MI" "MN" "MO" "MP" "MS" "MT" "NC" "ND" "NE" "NH" "NJ" "NM"
[37] "NV" "NY" "OH" "OK" "OR" "PA" "PR" "RI" "SC" "SD" "TN" "TX"
[49] "UM" "UT" "VA" "VI" "VT" "WA" "WI" "WV" "WY"