时间戳

首页 > 解决方案 > 匹配特殊字符前的字符串

r - 匹配特殊字符前的字符串

问题描述

我正在尝试匹配两列中的字符串并在“：”之前返回不匹配。如果 x2x, y67y，它不应该返回，因为 x 仍然是 x 而 y 仍然是 y。

我不想匹配“：十进制”。如果 x2y 在两列中，则它是一个匹配项（无论特殊字符后的小数点不匹配） 输入：

input <- structure(list(x = structure(c(1L, 2L, 3L, 3L), .Label = c("A", 
"B", "C"), class = "factor"), y = structure(c(2L, 3L, 1L, 4L), .Label = c("A", 
"B", "C", "D"), class = "factor"), x_val = c("x2x:0.12345,y67h:0.06732,d7j:0.032647", 
"x2y:0.26345,y67y:0.28320,d7r:0.043647", "x2y:0.23435,y67y:0.28310,d7r:0.043547", 
"x2y:0.23435,y67y:0.28330,d7r:0.043247"), y_val = c("x2y:0.33134,y67y:0.3131,d7r:0.23443", 
"x2y:0.34311,y67y:0.14142,d7r:0.31431", "x2x:0.34314,y67h:0.14141,d7j:0.453145", 
"x67b:0.31411,g72v:0.3134,b8c:0.89234")), row.names = c(NA, -4L
), class = "data.frame")

输出：

output <- structure(list(x = structure(c(1L, 2L, 3L, 3L), .Label = c("A", 
"B", "C"), class = "factor"), y = structure(c(2L, 3L, 1L, 4L), .Label = c("A", 
"B", "C", "D"), class = "factor"), x_val = c("x2x:0.12345,y67h:0.06732,d7j:0.032647", 
"x2y:0.26345,y67y:0.28320,d7r:0.043647", "x2y:0.23435,y67y:0.28310,d7r:0.043547", 
"x2y:0.23435,y67y:0.28330,d7r:0.043247"), y_val = c("x2y:0.33134,y67y:0.3131,d7r:0.23443", 
"x2y:0.34311,y67y:0.14142,d7r:0.31431", "x2x:0.34314,y67h:0.14141,d7j:0.453145", 
"x67b:0.31411,g72v:0.3134,b8c:0.89234"), diff_x = c("y67h:0.06732,d7j:0.03264", 
NA, "x2y:0.23435,d7r:0.043547", "x2y:0.23435,y67y:0.28330,d7r:0.043247"
), diff_y = c("x2y:0.33134,d7r:0.23443", NA, "y67h:0.14141,d7j:0.453145", 
"x67b:0.31411,g72v:0.3134,b8c:0.89234")), row.names = c(NA, -4L
), class = "data.frame")

当我只想匹配“：”字符时遇到问题。以下代码取自此问题：https ://stackoverflow.com/a/55285959/5150629 。

library(dplyr)
library(purrr)

I %>% mutate(diff_x = map2_chr(strsplit(x_val, split = ", "), 
                               strsplit(y_val, split = ", "), 
                               ~paste(grep('([a-z])(?>\\d+)(?!\\1)', setdiff(.x, .y), 
                                           value = TRUE, perl = TRUE), 
                                           collapse = ", ")) %>%
               replace(. == "", NA), 
             diff_y = map2_chr(strsplit(x_val, split = ", "), 
                               strsplit(y_val, split = ", "), 
                               ~paste(grep('([a-z])(?>\\d+)(?!\\1)', setdiff(.y, .x), 
                                           value = TRUE, perl = TRUE),
                                           collapse = ", ")) %>%
               replace(. == "", NA))

谁能帮忙？谢谢！

标签： rdplyrpurrr

解决方案

我在https://stackoverflow.com/a/55285959/5150629中修改了我的答案以适应这个问题：

library(dplyr)
library(purrr)

df %>% 
  mutate(
    diff_x = map2_chr(
      strsplit(x_val, split = ","), 
      strsplit(y_val, split = ","), 
      ~ {
        setdiff(sub(":.+$", "", .x), sub(":.+$", "", .y)) %>%
          grep('([a-z])(?>\\d+)(?!\\1)', ., value = TRUE, perl = TRUE) %>%
          sapply(grep, .x, value = TRUE) %>%
          paste(collapse = ", ") %>%
          replace(. == "", NA)
      }
    ),  
    diff_y = map2_chr(
      strsplit(x_val, split = ","), 
      strsplit(y_val, split = ","), 
      ~ {
        setdiff(sub(":.+$", "", .y), sub(":.+$", "", .x)) %>%
          grep('([a-z])(?>\\d+)(?!\\1)', ., value = TRUE, perl = TRUE) %>%
          sapply(grep, .y, value = TRUE) %>%
          paste(collapse = ", ") %>%
          replace(. == "", NA)
      }
    )
  )

输出：

  x y                                 x_val                                 y_val                     diff_x
1 A B x2x:0.12345,y67h:0.06732,d7j:0.032647   x2y:0.33134,y67y:0.3131,d7r:0.23443 y67h:0.06732, d7j:0.032647
2 B C x2y:0.26345,y67y:0.28320,d7r:0.043647  x2y:0.34311,y67y:0.14142,d7r:0.31431                       <NA>
3 C A x2y:0.23435,y67y:0.28310,d7r:0.043547 x2x:0.34314,y67h:0.14141,d7j:0.453145  x2y:0.23435, d7r:0.043547
4 C D x2y:0.23435,y67y:0.28330,d7r:0.043247  x67b:0.31411,g72v:0.3134,b8c:0.89234  x2y:0.23435, d7r:0.043247
                                  diff_y
1               x2y:0.33134, d7r:0.23443
2                                   <NA>
3             y67h:0.14141, d7j:0.453145
4 x67b:0.31411, g72v:0.3134, b8c:0.89234

笔记：

  1. 由于我们只对比较字符串格式的第一部分感兴趣x1y:000000，因此我sub(":.+$", "", .x)为每个map2_chr输入参数添加了一个以首先删除该:000000部分。

  2. setdiff并且以下grep步骤按预期工作，以返回不匹配并排除格式为 的字符串x1x。

  3. sapply(grep, .x, value = TRUE)在第一个grep获取不匹配向量之后，并搜索它们对应的原始字符串（x1y:000000形式）。

  4. paste将不匹配的向量折叠成一个逗号分隔的列表。

推荐阅读