从字符串中提取前N位数字

Question

我希望从一些字符串中提取前两个数字。 假设数据如下：

ABC Conference Room Monitor - Z5580J    
ABC 19 Monitor    
ABC 24 Monitor for Video-Conferencing
ABC UltraSharp 24 Monitor -QU2482Z

期望输出结果：

55
19
24
24

- Jayesh Nagar

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可能是从字符串中提取前2个字符的重复问题。 - SHS

不，它不是 从字符串中提取前两个字符 的重复。数字不是任何字符。 - Wiktor Stribiżew

Answer 1

使用正则表达式解决方案，\\D匹配非数字字符，\\d{2}匹配前两个数字。

as.numeric(sub("\\D*(\\d{2}).*", "\\1", INPUT))
# [1] 55 19 24 24

数据：

INPUT <- c("ABC Conference Room Monitor - Z5580J",
           "ABC 19 Monitor",
           "ABC 24 Monitor for Video-Conferencing",
           "ABC UltraSharp 24 Monitor -QU2482Z")

- pogibas

Answer 2

另一种解决方案：

strings <- c('ABC Conference Room Monitor - Z5580J','ABC 19 Monitor','ABC 24 Monitor for Video-Conferencing','ABC UltraSharp 24 Monitor -QU2482Z')
x <- as.numeric(gsub("\\D", "", strings))
as.numeric(substring(as.character(x*100), 1, 2))

[1] 55 19 24 24

- Adamm

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为什么不直接用 as.numeric(substr(gsub("\\D", "", strings),1,2)) 呢？ - moodymudskipper

Answer 3

包stringr可能提供了最干净的解决方案：

stringr::str_extract(string, "\\d{2}")
 "55" "19" "24" "24"

- s_baldur

Answer 4

stringr 的一个解决方案是：

library(stringr)
string <- str_extract_all("ABC Conference Room Monitor - Z5580J","\\(?[0-9,.]+\\)?")[[1]]
# "\\(?[0-9,.]+\\)?" is the regex, extracts only numbers
as.numeric(substr(string , 1,2)) # this selects the first two elements
#as.numeric is optional

- RLave