英文:
How to extract a string between two points and a dot
问题
我想提取冒号后和点号前的数字序列，即22334455。我尝试使用gsub("\\:*", "", 11:22334455.CEL)，但结果如下：
11216803.CEL
如何修复gsub函数以仅获取22334455？
英文:
I have the following string in R:
11:22334455.CEL
I would like to extract only the number series after : and before ., that means
22334455
I was trying with gsub("\\:*", "", 11:22334455.CEL), but I got the following result:
11216803.CEL
How could I fix the gsub function to get only 22334455?
Thank you!
答案1
得分: 1
你可以使用正则表达式捕获组（括号 (\\d+)）来捕获你想要的内容。
sub(".*:(\\d+)\\..*", "\", "11:22334455.CEL")
[1] "22334455"
英文:
You can use a regex capture group (the parentheses (\\d+)) to capture what you want.
sub(".*:(\\d+)\\..*", "\", "11:22334455.CEL")
[1] "22334455"
答案2
得分: 0
gsub(".*:|\\..*", "", "11:22334455.CEL")
# [1] "22334455"
英文:
You can remove characters before ':' and after '.'
gsub(".*:|\\..*", "", "11:22334455.CEL")
# [1] "22334455"
答案3
得分: 0
使用stringr的str_extract与group。
\\d+用于检测一个或多个数字，这里在大括号内定义了捕获组，位于:和\\.（转义的句点）之间。
library(stringr)
str_extract("11:22334455.CEL", ":(\\d+)\\.", group = 1)
[1] "22334455"
英文:
Using stringrs str_extract with group.
\\d+ detects one or more digits, here between : and \\. (escaped period) within braces that define the capture group.
library(stringr)
str_extract("11:22334455.CEL", ":(\\d+)\\.", group = 1)
[1] "22334455"
答案4
得分: 0
使用base R中的trimws函数：
trimws("11:22334455.CEL", whitespace = ".*:|\\..*")
[1] "22334455"
英文:
Using trimws from base R
trimws("11:22334455.CEL", whitespace = ".*:|\\..*")
[1] "22334455"
答案5
得分: 0
你可以使用 str_extract 与正向后顾 (?<=:) 来确保匹配仅从冒号之后开始，以及正向先行 (?=\\.) 来确保匹配后必须跟着一个 .：
str_extract("11:22334455.CEL", "(?<=:)\\d+(?=\\.)")
[1] "22334455"
英文:
You can use str_extract with look-behind (?<=:) to assert that the match only starts after the colon, and look-ahead (?=\\.) to assert that the match must be followed by a .:
str_extract("11:22334455.CEL", "(?<=:)\\d+(?=\\.)")
[1] "22334455"
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