R语言 字符串拼接

1. paste {base}

语法：

paste (..., sep = " ", collapse = NULL)
paste0(..., collapse = NULL)

两个参数：sep字符串内的拼接符；collapse字符串间的拼接符。paste与paste0的区别：paste0参数sep默认为空字符，paste的参数sep默认为空格。

示例：

paste("1st", "2nd", "3rd", collapse = ", ")
[1] "1st 2nd 3rd"

paste("1st", "2nd", "3rd", sep = ", ")
[1] "1st, 2nd, 3rd"

paste(c("a", "b", "c"),c(1:3) , sep = ": ", collapse = "; ")
[1] "a: 1; b: 2; c: 3"

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2. str_c {stringr}

语法：

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

参数：与paste一致，但对NA的处理方法不一致。

示例：

library("stringr")
str_c("Letter: ", letters)
 [1] "Letter: a" "Letter: b" "Letter: c" "Letter: d" "Letter: e" "Letter: f" "Letter: g" "Letter: h"
 [9] "Letter: i" "Letter: j" "Letter: k" "Letter: l" "Letter: m" "Letter: n" "Letter: o" "Letter: p"
[17] "Letter: q" "Letter: r" "Letter: s" "Letter: t" "Letter: u" "Letter: v" "Letter: w" "Letter: x"
[25] "Letter: y" "Letter: z"

#str_c在对含NA的字符拼接后，结果仍然为NA
str_c(c("a", NA, "b"), "-d")
[1] "a-d" NA    "b-d"
#paste在对含NA的字符拼接后，NA被当作为“NA”字符串处理
paste(c("a", NA, "b"), "-d")
[1] "a -d"  "NA -d" "b -d"