R函数之字符串

character(lenght = 0)：

as.character(x, ...)：

is.character(x)：

#连接字符向量

paste(..., sep=" ", collapse=NULL)

#获取或替换字符串的一部分

substr(x, start, stop)

substring(text, first, last=1000000L)

substr(x, start, stop) <- value

substring(text, first, last=1000000L) <- value

#获取字符串长度

nchar(x, type="chars", allowNA=FALSE)  #type <- c("bytes", "chars", "width")

nzchar(x)

#分割字符向量mi

strsplit(x, split, fixed=FALSE, perl=FALSE, useBytes=FALSE) #fixed是否使用正则表达式， perl是否使用perl风格的正则表达式

#格式化打印

sprintf(fmt, ...)

grep(pattern, x, ignore.case = FALSE, perl = FALSE, value = FALSE,
     fixed = FALSE, useBytes = FALSE, invert = FALSE)


grepl(pattern, x, ignore.case = FALSE, perl = FALSE,
      fixed = FALSE, useBytes = FALSE)


sub(pattern, replacement, x, ignore.case = FALSE, perl = FALSE,
    fixed = FALSE, useBytes = FALSE)


gsub(pattern, replacement, x, ignore.case = FALSE, perl = FALSE,
     fixed = FALSE, useBytes = FALSE)


regexpr(pattern, text, ignore.case = FALSE, perl = FALSE,
        fixed = FALSE, useBytes = FALSE)


gregexpr(pattern, text, ignore.case = FALSE, perl = FALSE,
         fixed = FALSE, useBytes = FALSE)


regexec(pattern, text, ignore.case = FALSE,
        fixed = FALSE, useBytes = FALSE)