Question

我有一个数据框

> df
  letters numbers
1       A       1
2       B       2
3       C       3
4       D       4
5       E       5

并希望在连接行后得到以下结果：

"A1","B2","C3","D4","E5"

以便拥有以下内容：

c("A1","B2","C3","D4","E5")

以下代码出了什么问题？

> paste(df$letters, df$numbers, sep="",collapse='","')
[1] "A1\",\"B2\",\"C3\",\"D4\",\"E5"

Answer 1

对于data.frame，您可能需要尝试：

> do.call(paste0, df)
[1] "A1" "B2" "C3" "D4" "E5"

或者，如果您想要一个带逗号的单个字符串，请按以下步骤修改您的方法：

> paste0(df$letters, df$numbers, collapse = ", ")
[1] "A1, B2, C3, D4, E5"

在那里获取引号具有欺骗性：

> paste0('"', paste0(df$letters, df$numbers, collapse = '", "'), '"')
[1] "\"A1\", \"B2\", \"C3\", \"D4\", \"E5\""

看起来有反斜杠，但没有：

> cat(paste0('"', paste0(df$letters, df$numbers, collapse = '", "'), '"'))
"A1", "B2", "C3", "D4", "E5"
> nchar(paste0('"', paste0(df$letters, df$numbers, collapse = '", "'), '"'))
[1] 28

或者，也许您正在寻找dQuote，sQuote或shQuote（很难说不知道您为什么要做您正在做的事情）：

> noquote(paste(dQuote(paste0(df$letters, df$numbers)), collapse = ", "))
[1] “A1”, “B2”, “C3”, “D4”, “E5”
> noquote(paste(shQuote(paste0(df$letters, df$numbers)), collapse = ", "))
[1] 'A1', 'B2', 'C3', 'D4', 'E5'
> noquote(paste(sQuote(paste0(df$letters, df$numbers)), collapse = ", "))
[1] ‘A1’, ‘B2’, ‘C3’, ‘D4’, ‘E5’

Answer 2

\是转义字符，用于标识"，当在字符串本身中使用print和"时，R会在任何字符串周围打印。要摆脱\，您可以使用'代替"。另外，要在字符串周围获取'，也可以使用sprintf与paste结合使用{<1}}：

> paste(sprintf("'%s%s'", letters[1:10], 1:10), collapse = ",")
[1] "'a1','b2','c3','d4','e5','f6','g7','h8','i9','j10'"

Answer 3

R在字符串中将\"读作"。当你运行cat(paste0(df$letters, df$numbers, sep="",collapse='","'),"\n")时，你会看到。

Answer 4

这是我的帽子：

theString <- paste0(sprintf("\"%s%i\"", df$letters, df$numbers), collapse = ",")

cat(theString)
# "A1","B2","C3","D4","E5"

以“A1”，“B2”，“C3”形式连接行

4 个答案: