grep : escape "*"
On 1/9/2009 10:38 AM, David Hajage wrote:
Dear R useRs, Sorry for this foolish question, but I can't find how to escape the * character when using grep :
You use a backslash to escape the *. Unfortunately, to enter a backslash in an R string, you need to escape it. So the pattern is "\\*". Duncan Murdoch
grep("-", c("/3", "2*3", "4-4"))
[1] 3
grep("/", c("/3", "2*3", "4-4"))
[1] 1
grep("*", c("/3", "2*3", "4-4"))
Erreur dans grep("*", c("/3", "2*3", "4-4")) :
expression r?guli?re incorrecte '*'
De plus : Warning message:
In grep("*", c("/3", "2*3", "4-4")) :
erreur rgcomp : 'Expression r?guli?re pr?c?dente incorrecte'
grep("\*", c("/3", "2*3", "4-4"))
Erreur dans grep("*", c("/3", "2*3", "4-4")) :
expression r?guli?re incorrecte '*'
De plus : Warning messages:
1: '\*' est un code escape non reconnu dans une cha?ne de caract?res
2: code escape non reconnu ?limin? de "\*"
3: In grep("*", c("/3", "2*3", "4-4")) :
erreur rgcomp : 'Expression r?guli?re pr?c?dente incorrecte'
Best regards,
david
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