如何测试存储在向量中的字符串是否存在于 R 列表中？
要测试存储在向量中的字符串是否存在于 R 列表中，我们可以使用 mapply 函数。例如，如果我们有一个字符串向量 V 和一个名为 LIST 的列表，那么我们可以使用以下命令检查 V 中的元素是否存在于 LIST 中 -
mapply(`%in%`,V,LIST)
示例 1
以下代码段创建了一个向量和列表 -
x<-LETTERS[1:5]List<-list(a=sample(LETTERS[1:5],100,replace=TRUE),b=sample(LETTERS[21:26],100,replace=TRUE),c=letters[1:26],d=sample(LETTERS[1:10],100,replace=TRUE),e=sample(letters[1:5],50,replace=TRUE))List
创建以下向量和列表 -
$a [1] "C" "B" "D" "D" "C" "D" "B" "D" "B" "D" "B" "E" "A" "B" "E" "D" "C" "D"[19] "A" "B" "B" "D" "C" "D" "C" "D" "A" "D" "E" "D" "A" "E" "A" "B" "C" "A"[37] "A" "B" "A" "B" "A" "A" "A" "C" "B" "E" "D" "E" "D" "C" "C" "C" "D" "C"[55] "C" "D" "C" "B" "E" "D" "D" "E" "D" "E" "C" "D" "A" "E" "A" "B" "C" "B"[73] "A" "D" "B" "C" "E" "B" "D" "A" "B" "A" "B" "D" "A" "A" "A" "B" "A" "C"[91] "C" "D" "C" "A" "A" "A" "C" "A" "E" "A"$b [1] "Z" "Z" "U" "Z" "Y" "U" "Y" "U" "X" "Y" "Y" "Z" "X" "Z" "Z" "Z" "Y" "Z"[19] "X" "Y" "X" "W" "V" "X" "Z" "Z" "Z" "Z" "U" "W" "W" "Y" "W" "Z" "U" "W"[37] "V" "W" "W" "X" "Y" "V" "V" "W" "W" "Y" "Y" "Z" "X" "Y" "Z" "X" "U" "Z"[55] "Y" "Y" "Y" "W" "V" "U" "W" "X" "V" "Y" "V" "Y" "U" "X" "V" "X" "Z" "W"[73] "Y" "X" "U" "V" "U" "Y" "W" "V" "U" "Y" "V" "Y" "Z" "U" "V" "W" "Y" "U"[91] "U" "Y" "W" "U" "Z" "Y" "X" "Y" "Y" "X"$c [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s"[20] "t" "u" "v" "w" "x" "y" "z"$d [1] "G" "B" "G" "C" "F" "H" "J" "A" "H" "E" "H" "E" "I" "A" "E" "A" "I" "D"[19] "A" "D" "D" "C" "D" "J" "G" "C" "D" "G" "G" "A" "D" "C" "F" "G" "G" "J"[37] "F" "E" "D" "E" "E" "G" "F" "F" "I" "C" "C" "F" "C" "E" "D" "C" "D" "F"[55] "J" "G" "D" "G" "C" "H" "H" "A" "D" "B" "G" "C" "A" "J" "I" "D" "J" "C"[73] "F" "H" "C" "F" "G" "C" "G" "D" "J" "I" "C" "E" "I" "H" "D" "G" "B" "D"[91] "H" "I" "B" "E" "J" "I" "C" "G" "F" "J"$e [1] "a" "e" "b" "e" "d" "c" "c" "c" "e" "e" "e" "d" "e" "b" "c" "b" "a" "a" "c"[20] "b" "b" "d" "c" "a" "e" "a" "b" "e" "a" "e" "e" "c" "a" "b" "d" "a" "e" "e"[39] "b" "b" "e" "e" "d" "a" "e" "b" "e" "c" "d" "e"
现在，要检查 x 的元素是否在 List 中，请将以下代码添加到上面的代码段中 -
x<-LETTERS[1:5]List<-list(a=sample(LETTERS[1:5],100,replace=TRUE),b=sample(LETTERS[21:26],100,replace=TRUE),c=letters[1:26],d=sample(LETTERS[1:10],100,replace=TRUE),e=sample(letters[1:5],50,replace=TRUE)) mapply(`%in%`,x,List)
输出结果
如果您将上述所有给定的片段作为单个程序执行，它会生成以下输出 -
A B C D ETRUE FALSE FALSE TRUE FALSE
示例 2
以下代码段创建了一个向量和列表 -
y<-letters[1:5]List<-list(a=sample(letters[1:5],100,replace=TRUE),b=sample(letters[21:26],100,replace=TRUE),c=LETTERS[1:26],d=sample(letters[1:10],100,replace=TRUE),e=sample(LETTERS[1:5],50,replace=TRUE))List
创建以下向量和列表 -
$a [1] "c" "e" "b" "b" "a" "e" "b" "e" "a" "e" "a" "c" "c" "d" "c" "d" "e" "a"[19] "a" "a" "e" "b" "a" "a" "e" "a" "c" "e" "e" "e" "e" "e" "e" "e" "d" "a"[37] "e" "a" "c" "d" "c" "e" "a" "e" "a" "a" "a" "d" "d" "e" "e" "a" "d" "e"[55] "e" "e" "a" "a" "a" "a" "a" "c" "e" "a" "e" "a" "b" "c" "e" "d" "a" "a"[73] "e" "b" "a" "a" "b" "e" "b" "e" "b" "d" "c" "c" "d" "e" "c" "b" "d" "c"[91] "a" "a" "b" "e" "d" "a" "d" "e" "e" "b"$b [1] "v" "v" "w" "y" "y" "w" "z" "u" "z" "x" "z" "y" "v" "z" "v" "u" "x" "v"[19] "y" "y" "u" "x" "u" "u" "w" "y" "y" "z" "y" "z" "v" "y" "v" "z" "u" "x"[37] "w" "z" "x" "x" "w" "z" "w" "y" "z" "v" "v" "z" "v" "x" "v" "z" "v" "z"[55] "y" "x" "y" "v" "u" "z" "v" "y" "z" "w" "v" "z" "v" "z" "z" "v" "u" "u"[73] "u" "z" "y" "w" "w" "y" "w" "z" "x" "z" "y" "v" "v" "z" "v" "z" "y" "u"[91] "x" "y" "x" "u" "x" "w" "y" "z" "u" "w"$c [1] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" "K" "L" "M" "N" "O" "P" "Q" "R" "S"[20] "T" "U" "V" "W" "X" "Y" "Z"$d [1] "b" "f" "d" "f" "a" "b" "h" "e" "c" "j" "b" "e" "i" "b" "e" "c" "h" "a"[19] "g" "d" "h" "c" "c" "b" "b" "h" "g" "b" "d" "c" "e" "a" "a" "a" "a" "h"[37] "f" "a" "i" "a" "a" "j" "f" "i" "i" "e" "g" "a" "j" "e" "i" "g" "c" "g"[55] "h" "c" "c" "i" "b" "g" "b" "b" "g" "g" "g" "a" "h" "a" "i" "e" "g" "a"[73] "g" "h" "e" "b" "h" "h" "g" "e" "e" "i" "c" "g" "d" "h" "d" "f" "d" "b"[91] "h" "g" "e" "b" "g" "c" "a" "i" "c" "c"$e [1] "B" "E" "D" "B" "E" "B" "B" "B" "C" "B" "C" "E" "A" "B" "D" "D" "C" "B" "B"[20] "A" "A" "D" "B" "E" "C" "E" "E" "C" "E" "C" "B" "A" "B" "A" "A" "B" "E" "B"[39] "A" "E" "E" "A" "D" "B" "A" "A" "B" "E" "C" "D"
现在，要检查 y 的元素是否在 List 中，请将以下代码添加到上面的代码段中 -
y<-letters[1:5]List<-list(a=sample(letters[1:5],100,replace=TRUE),b=sample(letters[21:26],100,replace=TRUE),c=LETTERS[1:26],d=sample(letters[1:10],100,replace=TRUE),e=sample(LETTERS[1:5],50,replace=TRUE)) mapply(`%in%`,y,List)
输出结果
如果您将上述所有给定的片段作为单个程序执行，它会生成以下输出 -
a b c d eTRUE FALSE FALSE TRUE FALSE