[R] ? Exact pattern matching in GREP ?

[Derek Eder]

How is exact pattern matching achieved in GREP (and GREPlike) functions ? 

# Want: listing of all object names that end in *.lm
> objects(pattern="*.lm",pos=1)
#  ...  but get:  all objects that partially match *.lm, e.g., *.lme
[1] "j3.lm"  "J3.lme"  "j8.lm"  "J8.lme" 


#  Want:  position of string "4jan2002" in vector
> date.index <- grep("4jan2002", my.dates)
# .... but get:
> my.dates[date.index]
[1]  "4jan2002"  "24jan2002"   "14jan2002"   


Thank you.

Derek N. Eder
Göteborgs Universitet
Institutionen för klinisk neurovetenskap
Klinisk Neurofysiologi
Sahlgrenska universitetssjukhuset SS/SU
Blå straket 7, vån 3
SE 413 45  Göteborg
Sverige
Tlf. +46 (031) 34  244 14  (office)   NYT!
Tlf. +46 (031) 34 212 83  (laboratory)
Tlf. +46 0709 / 7 212 83 (mobil)
Fax. +46 (031) 82 81 63 
derek.eder at neuro.gu.se


Gothenburg University
Institute of Clinical Neuroscience,
Department of Clinical Neurophysiology
Salhgrenska Hospital  SU/SS
SE 413 45  Göteborg
Sweden



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