Rの正規表現 - RとLinuxと...

RとLinuxと...


Rの正規表現

  • [R_tmパッケージの使い方]

_ tokenize

今ひとつ気に入らない処理なのだが.

alice.raw <- readLines("alice.txt")

alice.raw3 <- strsplit(alice.raw,
  split = "[[:blank:]]|[[:punct:]]" ,
  extended = TRUE, perl = TRUE)[[1]]
alice.raw3[alice.raw3 != ""]

同じことだが

alice.raw3 <- unlist(strsplit(alice.raw,
  split = "[[:blank:]]|[[:punct:]]" ,
  extended = TRUE, perl = TRUE))
alice.raw3[nchar(alice.raw3) > 0]

_ 以下,整理する予定

# gsub(alice.raw, "") cuttokens <- proto(pre = function(this) {

this$words <- list()
}, fun = function(this, x) {
   if (is.null(words[[x]]))
     c(x, this)
})

gsubfn("\\w+", cuttokens, "the dog and the cat are in the house")

library(proto) library(gsubfn)

pwords <- proto(pre = function(this) {

this$words <- list()
}, fun = function(this, x) {
if (is.null(words[[x]]))
this$words[[x]] <- 0
this$words[[x]] <- words[[x]] + 1
paste0(x, "{", words[[x]], "}")
})

gsubfn("\\w+", pwords, "the dog and the cat are in the house do")

pwords2 <- proto(pre = function(this) {

this$words <- list()
}, fun = function(this, x) {
if (is.null(words[[x]]))
this$words[[x]] <- 0
this$words[[x]] <- words[[x]] + 1
list(x, words[[x]])
})
strapply("the dog and the cat are in the house", "\\w+", pwords2, combine = list, simplify = x ~ do.call(rbind, x))

alice.raw[alice.raw== "no"]

strapply(alice.raw, "\\w+", pwords2, combine = list, simplify = x ~ do.call(rbind, x))

pwords3 <- proto(pre = function(this) {

this$words <- list()
}, fun = function(this, x) {
if (is.null(words[[x]]))
this$words[[x]] <- 0
this$words[[x]] <- words[[x]] + 1
list(x, words[[x]])
})

# inspect(alice.DC2)1? alice.raw alice.raw2 <- gsub(",","",alice.raw) alice.raw3 <- strsplit(alice.raw, split = ":blank:?|:punct:?" , extended = TRUE, perl = TRUE)1? alice.raw3[alice.raw3 != ""]

# strapply(alice.raw, "\\w+", pwords2, combine = list, simplify = x ~ do.call(rbind, x))

# gsubfn("\\w+", pwords2, alice.raw)

########### </ tokenize する>

alice.raw <-

"Alice was beginning to get very tired of sitting by her sister on the bank, and of having nothing to do: once or twice she had peeped into the book her sister was reading, but it had no pictures or conversations in it, `and what is the use of a book,'thought Alice `without pictures or conversation?'"

strsplit(alice.raw, split = "[[:blank:]]|[[:punct:]]" ,
   extended = TRUE, perl = TRUE)[[1]]

#これだとマッチしたところで空ベクトルができてしまうよう.また gsubfn パッケージを使うと

strapply(alice.raw, "\\w+", pwords2, combine = list,
  simplify = x ~ do.call(rbind, x))

# 正しく分割するが,頻度カウントでは部分一致を行ってしまう模様

##

install.packages("gsubfn")
install.packages("proto")
library("gsubfn")
demo("gsubfn-gries")

### Examples

grep("[a-z]", letters)
txt <- c("arm","foot","lefroo", "bafoobar")
if(any(i <- grep("foo",txt)))
  cat("'foo' appears at least once in\n\t",txt,"\n")
i # 2 and 4
txt[i]

jp.txt <- c("山本五十六","山下清","山田太郎")
j <- grep("山本",jp.txt)
jp.txt[j]

## Double all 'a' or 'b's; "\" must be escaped, i.e., 'doubled'

gsub("([ab])", "\\1_\\1_", "abc and ABC")

## aかbがあれば,それをアンダーバーでつなげて二重化する

# \\1 は perl での $1に対応

gsub("([ab])", "\\$1_\\$1_", "abc and ABC", perl = TRUE)

# Warning message:

# perl=TRUE は UTF-8 ロケールに対してのみ完全実装されています

gsub("[山]", "石", "山田太郎")
txt <- c("The", "licenses", "for", "most", "software", "are",
 "designed", "to", "take", "away", "your", "freedom",
 "to", "share", "and", "change", "it.",
  "", "By", "contrast,", "the", "GNU", "General", "Public",
  "License",
  "is", "intended", "to", "guarantee", "your", "freedom",
  "to",
  "share", "and", "change", "free", "software", "--",
  "to", "make", "sure", "the", "software", "is",
  "free", "for", "all", "its", "users")
( i <- grep("[gu]", txt) ) # indices
stopifnot( txt[i] == grep("[gu]", txt, value = TRUE) )

## Note that in locales such as en_US this includes B as the

## collation order is aAbBcCdEe? ...

(ot <- sub("[b-e]",".", txt))
txt[ot != gsub("[b-e]",".", txt)]
  #- gsub does "global" substitution

txt[gsub("g","#", txt) !=
   gsub("g","#", txt, ignore.case = TRUE)] # the "G" words

regexpr("en", txt)

gregexpr("e", txt)

## trim trailing white space

str.test <- 'Now is the time      '
sub(' +$', '', str.test)  ## spaces only
sub(' [[:space:]]+$', '', str.test) ## white space, POSIX-style
sub('\\s+$', '', str, perl = TRUE) ## Perl-style white space

## capitalizing

gsub("(\\w)(\\w*)", "\\U\\1\\L\\2", "a test of capitalizing",
   perl=TRUE)
gsub("\\b(\\w)", "\\U\\1", "a test of capitalizing", perl=TRUE)

########## gsubfn

## http://cran.r-project.org/src/contrib/Descriptions/gsubfn.html

library(gsubfn)

#

s <- "abc 10:20 def 30:40 50"
gsubfn("([0-9]+):([0-9]+)", ~as.numeric(x) + as.numeric(y), s,
   backref = -2)
gsubfn("([0-9]+):([0-9]+)", ~as.numeric(x) + as.numeric(y), s)

# gsubfn("([0-9]+):([0-9]+)", ~as.numeric(x) + as.numeric(y), s,

  backref = 2)

# demo("gsubfn-si")

dat <- c("3.5G", "88P", "19")
gsubfn("[MGP]$", ~c(M = "e6", G = "e9", P = "e12")[[x]], dat)

p <- proto(fun = function(this, x) paste0(x, "{", count, "}"))

## count については ?paste0 を見よ

class(p)

ls(p)

with(p, fun)

s <- c("the dog and the cat are in the house", "x y x")
gsubfn("\\w+", p, s)

##### Rwiki での関数 proto の説明

x <- matrix(1:25,5) # 説明用のオブジェクト
x
incrb <- function(y) y[,1] <- y[,1]+1
incrb(x) # 引数をコピーして,コピーに操作を加える
x # なのでx は変化しない
incrc <- function(x) {x[,1] <- x[,1]+1; return(x)}
# 変更した x のコピーを返す
x <- incrc(x)
# x -> x のコピー -> x という順序で x が変更される
x               # 変更後

##############

prt <- proto(mat = matrix(1:25, 5))
ls(prt)
prt$mat
incr <- function(x) with(x, mat[,1] <- mat[,1] + 1)
# テスト用関数、一見終了後は何も変化は無いように見える
incr(prt)# proto オブジェクト p に関数 incr を実行
prt$mat# p の mat 成分が何時の間にか変更されている!

cut.x <- as.character(cut(seq(1, 100), 5))
colMeans(strapply(cut.x, "[^][(),]+", as.numeric,
 simplify = TRUE))

fn$lapply(list(1:4, 1:5), ~LETTERS[x])

### 正規表現を使って区間をいじる ## 代表値の作成 library(gsubfn)

freq.dat <- read.table("data3/newspan3/aitobi3.span3.dat")

freq.table <- table( factor(cut(freq.dat$V1, breaks= seq(0,
   max(freq.dat)+3, 3))))
freq.lab <- labels(table( factor(cut(freq.dat$V1,
   breaks= seq(0, max(freq.dat)+3, 3)))))[[1]]
as.numeric(freq.lab)

freq.matrix <- strapply(freq.lab, "[^][(),]+", as.numeric,
   simplify = TRUE)

freq.repr <- numeric( ncol(freq.matrix))
for(i in 0:ncol(freq.matrix)){
#  print(freq.matrix[2,i] - 1)
 freq.repr[i] <- floor((freq.matrix[2,i] - 1) / 3  )
}

data.frame(repr = freq.repr, freq =  as.numeric(freq.table))
out.file3 <- paste(out.dir, "newspan3/", text.text,
   data.ext, ".span3", sep = "") # 区間幅 3
freq.span <-  as.numeric(dimnames(table(buntyo))[[1]])
write.table(table( factor(cut(buntyo$V1, breaks= seq(0,
   max(buntyo)+3, 3)))),
  file = out.file3, row.names = FALSE, col.names = FALSE,
     quote = FALSE)
     system(paste("./altmann3.pl", out.file3))
      system(paste("rm",  out.file3))
     system(paste("qkc -m -s ", out.file3, ".dat", sep=""))
library(Rstem)
getStemLanguages()

gesetz <- readLines("p2007/bsj/vorDemGesezt.txt")
length(gesetz)

gesetz <- fifo("p2007/bsj/vorDemGesezt.txt")

wordStem(gesetz[5], language = "german")

gesetz <- file(p2007/bsj/vorDemGesezt.txt")
close(gesetz)
readChar(gesetz[5])

wordStem("this was a pen", lang = "english")
wordStem(c("these", "are", "books"), lang = "english")
wordStem(c("He", "liked", "apples"), lang = "english")
wordStem(c("win", "winning", 'winner'))
wordStem(c("Er", "liest", "das", "Buch"),
   language = "german")

## test fixed-length strings

  zz <- file("testchar", "wb")
x <- c("a", "this will be truncated", "abc")
nc <- c(3, 10, 3)
zz <- file("testchar", "rb")
readChar(gesetz, nc)
readChar(zz, nchar(x)+3)
# need to read the terminator explicitly

close(zz)
unlink("testchar")

# system.file() gsub()

alice <-

"Alice was beginning to get very tired of sitting by her sister on the bank, and of having nothing to do"

z <- unlist(strsplit(alice, split =" "))
length(z)

strsplit(alice, split = c(" ",","))
strsplit(alice, split = (" , "))
con <- file("test.txt")
#
open(con)
for(i in 1:4) {
 x <- readLines(con, n=1)
 if(length(x)> 0){
   print(x)
 }
}
close(con)
#
con <- file("test.txt")
#

con <- file("test.txt")
open(con)

z <- 1
while(z){
 x <- readLines(con, n=1)
 if(length(x)> 0){
   print(x)
 }else{
   z <- 0
   break;
 }
}

close(con)
con <- file("test.txt")
open(con)
while(1){
 x <- readLines(con, n=1)
 if(length(x)> 0){
   print(x)
 }else{
   break;
 }
}
close(con)

### 読み込むたびにスペースで区切る

con <- file("test.txt")
open(con)
while(1){
 x <- readLines(con, n=1)
 if(length(x)> 0){
   z <- unlist(strsplit(x, " "))
   for(j in 1:length(z)){
     print(z[j])
   }
 }else{
   break;
 }
}
close(con)

### 読み込むたびに stemming する

con <- file("test.txt")
open(con)
while(1){
 x <- readLines(con, n=1)
 if(length(x) == 0 || x == ""){
   break;
 }
 else{
   x <-  gsub("\\.|\\,|\\?|\\!", "",  x)
   if(length(x)> 0 ){
     z <- unlist(strsplit(x, " "))
     for(j in 1:length(z)){
       cat(wordStem(z[j], lang = "english"), "\n")
       #print(z[j])
     }
   }
 }
}
close(con)
s <-

"These books are good. Our dogs, are, pretty. Oh! my gods!?"

s <- gsub("\\.|\\,|\\?|\\!", "",  s)
strsplit(s, " ")

# if(as.logical(s) != NA) print("NA")

s <- ""
length(s)
if(s == "") print ("empty")
x <- rpois(100, lam = 5)# いい加減な乱数で
table(cut(x, breaks = seq(0, max(x), 3)))# 頻度表を作る
table(cut(x, breaks = seq(0, max(x), 3), labels = F))
prop.table(cut(x, breaks = seq(0, max(x), 3)))#
as.numeric(noquote(labels(table(cut(x,
   breaks = seq(0, max(x), 3)))))[[1]])

x <- c(1,1,1,1,2, 5,5,5, 6,6)
table(cut(x, breaks = 0:max(x)))
table(cut(x, breaks = 0:max(x), lab = F))# 頻度表を作る
as.numeric(labels(table(cut(x,
   breaks = 0:max(x), lab = F)))[[1]])
table(cut(x, breaks = 0:max(x), lab = 0:max(x)))
# 頻度表を作る
 
Link: Rの備忘録(1706d)
Last-modified: 2007-11-24 (土) 18:24:36 (3921d)