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法律研究如何在 R 中移除字串中的第一個和最後一個字元？
要移除字串中的第一個和最後一個字元，我們可以使用 stringr 包中的 str_sub 函式。例如，如果一個單詞 tutorialspoint 被錯誤地輸入成 ttutorialspointt 並存儲在名為 x 的向量中，那麼為了移除第一個和最後一個“t”，我們可以使用命令 str_sub(x,2,−2)。
示例 1
library(stringr) x1<−"aallworldpopulations" str_sub(x1,2,−2)
輸出
[1] "allworldpopulation"
示例 2
x2<−c("AAlabamaa", "AAlaskaa", "AAmerican Samoaa", "AArizonaa", "AArkansass", "CCaliforniaa", "CColoradoo", "CConnecticutt", "DDelawaree", "DDistrict of Columbiaa", "FFloridaa", "GGeorgiaa", "GGuamm", "HHawaiii", "IIdahoo", "IIllinoiss", "IIndianaa", "IIowaa", "KKansass", "KKentuckyy", "LLouisianaa", "MMainee", "MMarylandd", "MMassachusettss", "MMichigann", "MMinnesotaa", "MMinor Outlying Islandss", "MMississippii", "MMissourii", "MMontanaa", "NNebraskaa", "NNevadaa", "NNew Hampshiree", "NNew Jerseyy", "NNew Mexicoo", "NNew Yorkk", "NNorth Carolinaa", "NNorth Dakotaa", "NNorthern Mariana Islandss", "OOhioo", "OOklahomaa", "OOregonn", "PPennsylvaniaa", "PPuerto Ricoo", "RRhode Islandd", "SSouth Carolinaa", "SSouth Dakotaa", "TTennesseee", "TTexasx", "UU.S. Virgin Islandss", "UUtahh", "VVermontt", "VVirginiaa", "WWashingtonn", "WWest Virginiaa", "WWisconsinn", "WWyomingg")
x2輸出
[1] "AAlabamaa" "AAlaskaa" [3] "AAmerican Samoaa" "AArizonaa" [5] "AArkansass" "CCaliforniaa" [7] "CColoradoo" "CConnecticutt" [9] "DDelawaree" "DDistrict of Columbiaa" [11] "FFloridaa" "GGeorgiaa" [13] "GGuamm" "HHawaiii" [15] "IIdahoo" "IIllinoiss" [17] "IIndianaa" "IIowaa" [19] "KKansass" "KKentuckyy" [21] "LLouisianaa" "MMainee" [23] "MMarylandd" "MMassachusettss" [25] "MMichigann" "MMinnesotaa" [27] "MMinor Outlying Islandss" "MMississippii" [29] "MMissourii" "MMontanaa" [31] "NNebraskaa" "NNevadaa" [33] "NNew Hampshiree" "NNew Jerseyy" [35] "NNew Mexicoo" "NNew Yorkk" [37] "NNorth Carolinaa" "NNorth Dakotaa" [39] "NNorthern Mariana Islandss" "OOhioo" [41] "OOklahomaa" "OOregonn" [43] "PPennsylvaniaa" "PPuerto Ricoo" [45] "RRhode Islandd" "SSouth Carolinaa" [47] "SSouth Dakotaa" "TTennesseee" [49] "TTexasx" "UU.S. Virgin Islandss" [51] "UUtahh" "VVermontt" [53] "VVirginiaa" "WWashingtonn" [55] "WWest Virginiaa" "WWisconsinn" [57] "WWyomingg"
示例
str_sub(x2,2,−2)
輸出
[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"
示例 3
x3<−c("AAKK", "AALL", "AARR", "AASS", "AAZZ", "CCAA", "CCOO", "CCTT", "DCDC", "DDEE", "FFLL", "GGAA", "GGUU", "HHII", "IIAA", "IIDD", "IILL", "IINN", "KKSS", "KKYY", "LLAA", "MMAA", "MMDD", "MMEE", "MMII", "MMNN", "MMOO", "MMPP", "MMSS", "MMTT", "NNCC", "NNDD", "NNEE", "NNHH", "NNJJ", "NNMM", "NNVV", "NNYY", "OOHH", "OOKK", "OORR", "PPAA", "PPRR", "RRII", "SSCC", "SSDD", "TTNN", "TTXX", "UUMM", "UUTT", "VVAA", "VVII", "VVTT", "WWAA", "WWII", "WWVV", "WWYY")
x3
[1] "AAKK" "AALL" "AARR" "AASS" "AAZZ" "CCAA" "CCOO" "CCTT" "DCDC" "DDEE"
[11] "FFLL" "GGAA" "GGUU" "HHII" "IIAA" "IIDD" "IILL" "IINN" "KKSS" "KKYY"
[21] "LLAA" "MMAA" "MMDD" "MMEE" "MMII" "MMNN" "MMOO" "MMPP" "MMSS" "MMTT"
[31] "NNCC" "NNDD" "NNEE" "NNHH" "NNJJ" "NNMM" "NNVV" "NNYY" "OOHH" "OOKK"
[41] "OORR" "PPAA" "PPRR" "RRII" "SSCC" "SSDD" "TTNN" "TTXX" "UUMM" "UUTT"
[51] "VVAA" "VVII" "VVTT" "WWAA" "WWII" "WWVV" "WWYY"
str_sub(x3,2,−2)
[1] "AK" "AL" "AR" "AS" "AZ" "CA" "CO" "CT" "CD" "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"
更新日期：09-Feb-2021
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