Question

我想从弦中提取血压。数据可能如下所示：

text <- c("at 10.00 seated 132/69", "99/49", "176/109",  
"10.12 I 128/51, II 149/51 h.9.16", "153/82 p.90 ja 154/81 p.86", 
"h:17.45", "not measured", "time 7.30 RR 202/97 p. 69")

我想提取模式＆＃34;数字/数字＆＃34; （即"132/69"）。在上面的例子中，预期的输出是一个列表：

[[1]]
[1] "132/69" 

[[2]]
[1] "99/49"

[[3]]
[1] "176/109"

[[4]]
[1] "128/51" "149/51"

[[5]]
[1] "153/82" "154/81" 

[[6]]
[1] ""

[[7]]
[1] ""

[[8]]
[1] "202/97"

我最接近的解决方案：

gsub( "^.*([0-9]{3}/[0-9]+).*","\\1", text)

不幸的是，在我的解决方案中，它不返回该模式的所有匹配情况，并且还返回一个根本没有所需模式的字符串。

Answer 1

regmatches(text, gregexpr("\\d+/\\d+", text))
#[[1]]
#[1] "132/69"
#
#[[2]]
#[1] "99/49"
#
#[[3]]
#[1] "176/109"
#
#[[4]]
#[1] "128/51" "149/51"
#
#[[5]]
#[1] "153/82" "154/81"
#
#[[6]]
#character(0)
#
#[[7]]
#character(0)
#
#[[8]]
#[1] "202/97"

Answer 2

如果您想获得所描述的确切输出，可以使用

library(stringr)
library(magrittr)
text <- c("at 10.00 seated 132/69", "99/49", "176/109",  
          "10.12 I 128/51, II 149/51 h.9.16", "153/82 p.90 ja 154/81 p.86", 
          "h:17.45", "not measured", "time 7.30 RR 202/97 p. 69")

str_extract_all(text, "\\d{2,3}/\\d{1,3}") %>%
  lapply(FUN = function(x) if (length(x) == 0) "" else x)

[[1]]
[1] "132/69"

[[2]]
[1] "99/49"

[[3]]
[1] "176/109"

[[4]]
[1] "128/51" "149/51"

[[5]]
[1] "153/82" "154/81"

[[6]]
[1] ""

[[7]]
[1] ""

[[8]]
[1] "202/97"

如果你想留在R基地，你也可以使用Roland的regmatches。

Answer 3

轻微＆amp; @ Benjamin的解决方案更紧凑，返回一个漂亮的，简单的字符向量，并且无需处理@ Roland列表中的0长度元素：

library(stringi)
library(purrr)

txt <- c("at 10.00 seated 132/69", "99/49", "176/109",  
         "10.12 I 128/51, II 149/51 h.9.16", "153/82 p.90 ja 154/81 p.86", 
         "h:17.45", "not measured", "time 7.30 RR 202/97 p. 69")

stri_match_all_regex(txt, "\\d{2,3}/\\d{1,3}") %>%
  flatten_chr() %>% 
  discard(is.na)
## [1] "132/69"  "99/49"   "176/109" "128/51"  "149/51"  "153/82"  "154/81"  "202/97"

提取模式＆＃34;数字/数字＆＃34;

3 个答案: