r：有条件地替换列子集中的值

Question

我有一个这样的数据框：

sport   contract start contract end visits spends purchases
basket   2013-10-01     2014-10-01   12      14      23
basket   2014-02-12     2015-03-03   23      11      7
football 2015-02-12     2016-03-03   23      11      7
basket   2016-07-17     2013-09-09   12       7      13

我想根据变量 "sport" 和 "contract start" 有条件地将列 [4:6] 替换为 NA。例如：

i1 <- which(df$sport =="basket" & df$contract_start>="2014-01-01")

将索引所有满足我的条件的行。是否有一段简单的代码可以添加到上面，在上述条件下将 df[4:6] 替换为 NA？我想以这样的方式结束：

sport   contract start contract end visits spends purchases
basket   2013-10-01     2014-10-01   12      14      23
basket   2014-02-12     2015-03-03   NA      NA      NA
football 2015-02-12     2016-03-03   23      11      7
basket   2016-07-17     2013-09-09   NA      NA      NA

谢谢！ A.

Answer 1

您可以简单地指定要用 NA 替换的行和列，然后将 NA 分配给它：

df[df$sport =="basket" & df$contract_start>="2014-01-01", 4:6] <- NA

df
#      sport contract_start contract_end visits spends purchases
# 1   basket     2013-10-01   2014-10-01     12     14        23
# 2   basket     2014-02-12   2015-03-03     NA     NA        NA
# 3 football     2015-02-12   2016-03-03     23     11         7
# 4   basket     2016-07-17   2013-09-09     NA     NA        NA

Answer 2

library("data.table")
setDT(df)
df[i = sport == "basket" & contract_start >= "2014-01-01", 
   j = c("visits", "spends", "purchases") := NA]

> df
      sport contract_start contract_end visits spends purchases
1:   basket     2013-10-01   2014-10-01     12     14        23
2:   basket     2014-02-12   2015-03-03     NA     NA        NA
3: football     2015-02-12   2016-03-03     23     11         7
4:   basket     2016-07-17   2013-09-09     NA     NA        NA

上述代码使用 my_cols 变量的变体：

my_cols <- names(df)[4:6]
df[i = sport == "basket" & contract_start >= "2014-01-01", 
   j = (my_cols) := .(NA)]

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