R语言字符串函数

#字符串连接:
paste() #paste(..., sep = " ", collapse = NULL)

#字符串分割:
strsplit() #strsplit(x, split, extended = TRUE, fixed = FALSE, perl = FALSE)

#计算字符串的字符数:
nchar()

#字符串截取:
substr(xstartstop)
substring(textfirstlast = 1000000)
substr(xstartstop) <- value
substring(textfirstlast = 1000000) <- value

 substr("abcdef", 2, 4)
[1] "bcd"

> x <- "1234567890"
> substr(x, 3, 3)
[1] "3"
> > substr(x, 5, 7) [1] "567" > > substr(x, 4, 4) <- "A" > x [1] "123A567890" > > substr(x, 2, 4) <- "TTF" > x [1] "1TTF567890" > > substr(x, 9, 12) <- "ABCD" > x [1] "1TTF5678AB" > > substring(x, 5) [1] "5678AB" > > substring(x, 5) <- "..." > x [1] "1TTF...8AB"




#字符串替换及大小写转换:
chartr(oldnewx)
tolower(x)
toupper(x)
casefold(xupper = FALSE)

x=gsub(old_strin, new_string, x) # replace string 字符串替换

grepl(value, chars) # chars contains value? (TRUE, FALSE)

 

#字符串比较:

if(as.character(x)==as.character(y))

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