如何根据其他列中的字符在字符串中找到匹配项？

Question

我有这些数据：

df1 <- data.frame(matrix(, nrow=2, ncol=2))
colnames(df1) <- c("ca", "ea")
df1$ca <- c("A=C,T=G", "T=C,G=G")
df1$ea <- c("G", "T")

我想创建一个名为“match”的新列，它为我提供“ca”列中的字母等于“ea”列中的字母。所以我的输出看起来像这样：

df1 <- data.frame(matrix(, nrow=2, ncol=2))
colnames(df1) <- c("ca", "ea")
df1$ca <- c("A=C,T=G", "T=C,G=G")
df1$ea <- c("G", "T")
df1$match <- c("T", "C")

这很棘手，因为在第一个实例中，我要匹配的字母在“=”之后，但在第二个实例中，它在它之前。

Answer 1

我相信这对你有用:

df1 <- data.frame(matrix(, nrow=2, ncol=2))
colnames(df1) <- c("ca", "ea")
df1$ca <- c("A=C,T=G", "T=C,G=G")
df1$ea <- c("G", "T")

my_f <- function(x) {
  my_pattern <- paste("[ACGT]=", df1[x, "ea"], "|", df1[x, "ea"], "=[ACGT]", sep 
= "")
  my_a <- str_extract_all(string = df1[x, "ca"], pattern = my_pattern, simplify = TRUE)
  my_pattern <- paste(df1[x, "ea"], "|=", sep = "")
  my_a <- gsub(pattern = my_pattern, replacement = "", x = my_a)
  return (my_a)
}
df1$match <- lapply(1:nrow(df1), my_f)

Answer 2

library(tidyverse)

df1 <- data.frame(matrix(, nrow = 2, ncol = 2))
colnames(df1) <- c("ca", "ea")
df1$ca <- c("A=C,T=G", "T=C,G=G")
df1$ea <- c("G", "T")
df1
#>        ca ea
#> 1 A=C,T=G  G
#> 2 T=C,G=G  T

df1 %>%
  mutate(
    match = ea %>% map2_chr(ca, function(ea, ca) {
      ca %>%
        str_split(",") %>%
        simplify() %>%
        keep(~ str_detect(.x, ea)) %>%
        str_remove_all(str_glue("[=|{ea}]"))
    })
  )
#>        ca ea match
#> 1 A=C,T=G  G     T
#> 2 T=C,G=G  T     C

^{由 reprex package (v2.0.1)}

于 2021-12-08 创建

Answer 3

这是另一个 tidyverse 解决方案，使用正则表达式可能更简单一些。您需要 R > 4.0 才能使用 |> 管道运算符，如果不是这种情况，只需将其替换为 %>%.

library(tidyverse)

df1 |>
  # add a named match column as an extracted string by the following 
  # two possible patterns
  mutate(match = str_extract(ca, 
                             # Search for the letter preceded by ea=
                             paste0(paste0("(?<=",ea,"\=)","[A-Z]"),
                                    # or
                                    "|",
                                    # search for the letter followed by =ea
                                    paste0("[A-Z]","(?=\=",ea,")"))))

#        ca ea match
# 1 A=C,T=G  G     T
# 2 T=C,G=G  T     C

Answer 4

简单的好机会branch reset group

df1 <- data.frame(matrix(, nrow=2, ncol=2))
colnames(df1) <- c("ca", "ea")
df1$ca <- c("A=C,T=G", "T=C,G=G")
df1$ea <- c("G", "T")
df1$match <- c("T", "C")

mapply(
  function(p, x)
  gsub(sprintf('(?|%s=(.)|(.)=%s)|.', p, p), '\1', x, perl = TRUE),
  df1$ea, df1$ca, USE.NAMES = FALSE
)
# [1] "T" "C"

如何根据其他列中的字符在字符串中找到匹配项？

How to find a match within a string based on character from other column?

r

str-replace