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  1. vec <- c("mcq_q9", "mcq_q10", "mcq_q11", "mcq_q12",   "mcq_q1.factor", "mcq_q2.factor", "mcq_q10.factor", "mcq_q11.factor", "mcq_q12.factor")
  2. grep("mcq_q[0-9]+(?![\\d\\.])", vec, perl = T)
  3.  
  4.  
  5.  
  6.  
Success #stdin #stdout 0.16s 175424KB
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stdin 
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stdout 
[1] 1 2 3 4
https://ideone.com/Ow1iBJ
language:
R (R 3.5.2)
created:
7 years ago
visibility:
public

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