如何使用两个相关列投射数据框？

Question

我的数据框如下所示。

"id" "question" "response"  "suite"
1    "x"        "a"         "1"
2    "y"        "b"         "1"
3    "x"        "c"         "1"
4    "y"        "d"         "1"
5    "x"        "e"         "2"
6    "y"        "f"         "2"

到目前为止，Dcast（在reshape2中）似乎是我最好的选择。

result <- dcast(df, id + suite ~ question, value.var = "response")

虽然我最终得到了这个;

"id" "suite" "x" "y"
1    "1"     "1" "1"
2    "1"     "1" "1"
3    "1"     "1" "1"
4    "1"     "1" "1"
5    "2"     "1" "1"
6    "2"     "1" "1"

随着错误;

Aggregation function missing: defaulting to length(response)

我怎样才能获得第二种格式而不会在＆＃34;响应中丢失我的字符串＆＃34;列？