R help - Jun 2012 - matching a string with multiple conditions using grep

Suppose I have a vector  ["A_cont_1", "A_cont_12",
"B_treat_8",
"AB_cont_22", "cont_21_Aa"], I hope I can extract the
strings which include
3 short strings, say "A", "cont" and "2",  that is
to say, "A_cont_12",
"AB_cont_22" and  "cont_21_Aa" will be extract, using a
relatively short
code (using grep?).
Would you please to give some idea? Thank you !

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Hello,

Try the following.


wanted <- c("A_cont_12", "AB_cont_22",
"cont_21_Aa")

x <- c("A_cont_1", "A_cont_12", "B_treat_8",
"AB_cont_22", "cont_21_Aa")

pattern <- c("A", "cont", "2")

ix <- Reduce(`&`, lapply(pattern, grepl, x))  # This does the trick
identical(wanted, x[ix])


See ?Reduce.

Hope this helps,

Rui Barradas

Em 23-06-2012 11:19, Zhipeng Wang escreveu:
> Suppose I have a vector  ["A_cont_1", "A_cont_12",
"B_treat_8",
> "AB_cont_22", "cont_21_Aa"], I hope I can extract the
strings which include
> 3 short strings, say "A", "cont" and "2", 
that is to say, "A_cont_12",
> "AB_cont_22" and  "cont_21_Aa" will be extract, using a
relatively short
> code (using grep?).
> Would you please to give some idea? Thank you !
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

Hi,

Try this:
vec1<-c("A_cont_1", "A_cont_12", "B_treat_8",
"AB_cont_22", "cont_21_Aa")
vec2<-grep("(A){0,1}.*cont.*2",vec1)

vec1[vec2]
[1] "A_cont_12"? "AB_cont_22" "cont_21_Aa"


A.K.




----- Original Message -----
From: Zhipeng Wang <wangz at kuhp.kyoto-u.ac.jp>
To: r-help at r-project.org
Cc: 
Sent: Saturday, June 23, 2012 6:19 AM
Subject: [R] matching a string with multiple conditions using grep

Suppose I have a vector? ["A_cont_1", "A_cont_12",
"B_treat_8",
"AB_cont_22", "cont_21_Aa"], I hope I can extract the
strings which include
3 short strings, say "A", "cont" and "2",? that is
to say, "A_cont_12",
"AB_cont_22" and? "cont_21_Aa" will be extract, using a
relatively short
code (using grep?).
Would you please to give some idea? Thank you !

??? [[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.