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R_note -- The Exploration of Statistical Software R (統計軟體 R 深度歷險)
About R_note
Reference
MS Windows

Batch jobs
Function
Data/MySQL
Plot
String/Parse

Remark Lines
Classes/S3
S4 Methods
Batch more
Environment

Good Coding
Fast Loop
LAM/MPI/Rmpi
Recursion

PHP Call R
Basic C
R Call Fortran/C
R Call GSL
C Call R API
C Call R Objects
Standalone

Make Packages
C Pointer
Debug




Section: String/Parse

  • String process
    Function paste(), nchar(), strsplit(), substr(), match(), ...

        
    a <- paste("string", 9:1, ".txt", sep = "")
    nchar(a)
    strsplit(a, "\\.")
    substr(a, 1, 6) <- "Substr"; a
    match("Substr9.txt", a)
    

  • Regulas expression
    Function grep(), gsub(), ...

        
    a <- paste("string", 9:1, ".txt", sep = "")
    grep("([1,3,5-7])", a)
    b <- paste("string", 9:1, ".txt", sep = "", collapse = " ")
    gsub("([1,3,5-7]).(txt)", "_\\1-\\2", b)
    

  • Expression and Parse
    Function expression(), parse(), ... These are important functions for computing in text and useful for processing automatically jobs as shown in "Batch more".

        
    a <- 0.05
    expression(alpha == 0.05)
    (ret <- parse(text = paste("alpha == ", a, sep = "")))
    plot(1, 1, main = ret)
    text(1, 1.2, ret)
    


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Maintained: Wei-Chen Chen
E-Mail: wccsnow @ gmail.com
Last Revised: Dec 12 2016, 09:44 (CST Taipei, Taiwan)
Created: Oct 06 2003
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