Question

我有一个字符串向量，与此类似，但有更多元素：

s <- c("CGA-DV-558_T_90.67.0_DV_1541_07", "TC-V-576_T_90.0_DV_151_0", "TCA-DV-X_T_6.0_D_A2_07", "T-V-Z_T_2_D_A_0", "CGA-DV-AW0_T.1_24.4.0_V_A6_7", "ACGA-DV-A4W0_T_274.46.0_DV_A266_07")

我想使用一个函数来提取分隔符的第n个和第i个实例之间的字符串＆＃34; _＆＃34;。例如，第二个（n = 2）和第三个（i = 3）实例之间的字符串，以获取此信息：

[1] "90.67.0"  "90.0"     "6.0"      "2"        "24.4.0"   "274.46.0"

或者，如果n = 4且i = 5＆＃34;

[1] "1541" "151"  "A2"   "A"    "A"    "A266"

有什么建议吗？谢谢你的帮助！

Answer 1

您可以使用gsub

执行此操作

n = 2
i = 3

pattern1 = paste0("(.*?_){", n,  "}")
temp = gsub(pattern1, "", s)
pattern2 = paste0("((.*?_){", i-n,  "}).*")
temp = gsub(pattern2, "\\1", temp)
temp = gsub("_$", "", temp)
[1] "1541" "151"  "A2"   "A"    "A6"   "A266"

Answer 2

#FUNCTION
foo = function(x, n, i){
    do.call(c, lapply(x, function(X)
        paste(unlist(strsplit(X, "_"))[(n+1):(i)], collapse = "_")))
}

#USAGE
foo(x = s, n = 3, i = 5)
#[1] "DV_1541" "DV_151"  "D_A2"    "D_A"     "V_A6"    "DV_A266"

Answer 3

第三种方法，使用<html> <head> <style> .astext { background:none; border:none; margin:0; padding:0; } </style> </head> <body> <button class="astext"><span>Button 1</span></button> <button class="astext"><span>Button 2</span></button> <button class="astext"><span>Button 3</span></button> <button class="astext"><span>Button 4</span></button> </body> </html>进行提取，substring查找位置

gregexpr

R在分隔符的第n个和第i个实例之间提取字符串

3 个答案: