R之字串相關

1.strsplit(m,n)  分割字串:將字串m,在含有字元n的地方進行分割

如：strsplit("abcdef","e"):  

結果為：

[[1]]

[1] "abcd" "f" 

strsplit(c("ab","cde","mnd"),"e")  結果為：

[[1]]

[1] "ab"

[[2]]

[1] "cd"

[[3]]

[1] "mnd"

2.substr(m,index1,length):擷取字串m,從index1索引處擷取長度為length的字串；

> substr("abcde",1,3)

[1] "abc"

#字串連線：

paste

() #paste(..., sep = " ", collapse = null)

#字串分割：

strsplit

() #strsplit(x, split, extended = true, fixed = false, perl = false)

#計算字串的字元數：

nchar

()#字串擷取：

substr

(x, start

, stop

)substring

(text

, first, last = 1000000

)substr

(x, start

, stop

) <- value

substring

(text

, first, last = 1000000

) <- value

#字串替換及大小寫轉換：

chartr

(old, new

, x)

tolower

(x)toupper

(x)casefold

(x, upper = false)

字元完全匹配

grep

()字元不完全匹配

agrep

()字元替換

gsub

()#以上這些函式均可以通過perl=true來使用正規表示式。

grep

(pattern, x, ignore.case = false

, extended = true

,perl = false

, value = false

, fixed = false

, usebytes = false

)sub

(pattern, replacement, x,

ignore.case = false

, extended = true

, perl = false

,fixed = false

, usebytes = false

)gsub

(pattern, replacement, x,

ignore.case = false

, extended = true

, perl = false

,fixed = false

, usebytes = false

)regexpr

(pattern, text

, ignore.case = false

, extended = true

,perl = false

, fixed = false

, usebytes = false

)gregexpr

(pattern, text

, ignore.case = false

, extended = true

,perl = false

, fixed = false

, usebytes = false

)see

also:

regular

expression

(aka

'regexp'

)for

thedetails

ofthe

pattern

specification.

'glob2rx'

toturn

wildcard

matches

into

regular

expressions.

'agrep'

for

matching.

'tolower'

, 'toupper'

and'chartr'

for

character

translations.

'charmatch'

, 'pmatch'

, 'match'

.'apropos'

uses

regexps

andhas

nice

examples.

R之字串相關

1.strsplit m,n 分割字串 將字串m,在含有字元n的地方進行分割 如 strsplit abcdef e 結果為 1 1 abcd f strsplit c ab cde mnd e 結果為 1 1 ab 2 1 cd 3 1 mnd 2.substr m,index1,length 擷...

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