如何识别和提取R中的字母数字字符 [英] How to recognise and extract alpha numeric characters in R
问题描述
我想从R.中的分句中提取字母数字字符
我试过以下内容: aa = grep([:alnum:],abc)
code> integer(0),但它返回1,不应该是这种情况,因为abc
不是字母数字。
我在这里错过了什么?
基本上我在寻找一个函数,它只搜索字母和数字组合的字符,例如:ABC-0112,PCS12SCH
预先感谢您的帮助。 p>
[[:alnum:]]
匹配字母或数字。为了匹配包含两者的字符串,您应该使用
x < - c(ABC,ABc12 , - A-1,abc--,89 = A)
grep((。* [[:alpha:]。* [[:digit:]] |。* [[:digit:]]。* [[:alpha:]]),x)
#[1] 2 3 5
或
which(grepl([[:alpha:]], x)& grepl([[:digit:]],x))
#[1] 2 3 5
I want to extract alphanumeric characters from a partiular sentence in R. I have tried the following:
aa=grep("[:alnum:]","abc")
.This should return integer(0)
,but it returns 1,which should not be the case as "abc"
is not an alphanumeric.
What am I missing here?
Essentially I am looking for a function,that only searches for characters that are combinations of both alphabets and numbers,example:"ABC-0112","PCS12SCH"
Thanks in advance for your help.
[[:alnum:]]
matches alphabets or digits. To match the string which contains the both then you should use,
x <- c("ABC", "ABc12", "--A-1", "abc--", "89=A")
grep("(.*[[:alpha:]].*[[:digit:]]|.*[[:digit:]].*[[:alpha:]])", x)
# [1] 2 3 5
or
which(grepl("[[:alpha:]]", x) & grepl("[[:digit:]]", x))
# [1] 2 3 5
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