替换 R 数据框中变量中的特定字符

Question

我要全部更换, , - , ) , (和 (空格)与 .来自示例数据帧中的变量 DMA.NAME。我引用了三个帖子并尝试了他们的方法，但都失败了。:

Replacing column values in data frame, not included in list

R replace all particular values in a data frame

Replace characters from a column of a data frame R

方法一

> shouldbecomeperiod <- c$DMA.NAME %in% c("-", ",", " ", "(", ")")
c$DMA.NAME[shouldbecomeperiod] <- "."

方法二

> removetext <- c("-", ",", " ", "(", ")")
c$DMA.NAME <- gsub(removetext, ".", c$DMA.NAME)
c$DMA.NAME <- gsub(removetext, ".", c$DMA.NAME, fixed = TRUE)

Warning message:
In gsub(removetext, ".", c$DMA.NAME) :
  argument 'pattern' has length > 1 and only the first element will be used

方法三

> c[c == c(" ", ",", "(", ")", "-")] <- "."

示例数据框

> df
DMA.CODE                  DATE                   DMA.NAME       count
111         22 8/14/2014 12:00:00 AM               Columbus, OH     1
112         23 7/15/2014 12:00:00 AM Orlando-Daytona Bch-Melbrn     1
79          18 7/30/2014 12:00:00 AM        Boston (Manchester)     1
99          22 8/20/2014 12:00:00 AM               Columbus, OH     1
112.1       23 7/15/2014 12:00:00 AM Orlando-Daytona Bch-Melbrn     1
208         27 7/31/2014 12:00:00 AM       Minneapolis-St. Paul     1

我知道问题所在 - gsub使用模式和只有第一个元素。另外两种方法是在整个变量中搜索精确值，而不是在值内搜索特定字符。

Answer 1

您可以使用特殊组[:punct:]和 [:space:]像这样的模式组( [...] )内部:

df <- data.frame(
  DMA.NAME = c(
    "Columbus, OH",
    "Orlando-Daytona Bch-Melbrn",
    "Boston (Manchester)",
    "Columbus, OH",
    "Orlando-Daytona Bch-Melbrn",
    "Minneapolis-St. Paul"),
  stringsAsFactors=F)
##
> gsub("[[:punct:][:space:]]+","\\.",df$DMA.NAME)
[1] "Columbus.OH"                "Orlando.Daytona.Bch.Melbrn" "Boston.Manchester."         "Columbus.OH"               
[5] "Orlando.Daytona.Bch.Melbrn" "Minneapolis.St.Paul"