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法律研究如何在 R 中移除字符串中的第一个和最后一个字符？
要移除字符串中的第一个和最后一个字符，我们可以使用 stringr 包中的 str_sub 函数。例如，如果一个单词 tutorialspoint 被错误地输入成 ttutorialspointt 并存储在名为 x 的向量中，那么为了移除第一个和最后一个“t”，我们可以使用命令 str_sub(x,2,−2)。
示例 1
library(stringr) x1<−"aallworldpopulations" str_sub(x1,2,−2)
输出
[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输出
[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)
输出
[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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