不確定調用這個操作,Google沒有幫助。R:字符串的'相乘'dataframe列
說我有兩個簡單的dataframes這樣的:
df1 <- data.frame(factor1 = c("a", "b", "c"))
df2 <- data.frame(factor2 = c("x", "y", "z"))
> df1
factor1
1 a
2 b
3 c
> df2
factor2
1 x
2 y
3 z
我怎樣才能得到格式化這樣的數據幀:
factor1 factor2
1 a x
2 a y
3 a z
4 b x
5 b y
6 b z
7 c x
8 c y
9 c z
我認爲,這種操作可能涉及dataframes乘以,但這是行不通的:
> df1 * df2
factor1
1 NA
2 NA
3 NA
Warning message:
In Ops.factor(left, right) : ‘*’ not meaningful for factors
同樣的問題在這裏的另一種選擇:https://stackoverflow.com/questions/4309217/cartesian-product-data-frame-in-r – snoram