我试图将DataFrame中一列的数字类型从整数改为浮点数。这应该很简单,但它并没有奏效。数据类型仍然是整数。我错过了什么吗?
In [2]: using DataFrames
df = DataFrame(A = 1:4, B = ["M", "F", "F", "M"])
Out [2]: 4x2 DataFrame
| Row | A | B |
|-----|---|-----|
| 1 | 1 | "M" |
| 2 | 2 | "F" |
| 3 | 3 | "F" |
| 4 | 4 | "M" |
In [3]: df[:,:A] = float64(df[:,:A])
Out [3]: 4-element DataArray{Float64,1}:
1.0
2.0
3.0
4.0
In [4]: df
Out [4]: 4x2 DataFrame
| Row | A | B |
|-----|---|-----|
| 1 | 1 | "M" |
| 2 | 2 | "F" |
| 3 | 3 | "F" |
| 4 | 4 | "M" |
In [5]: typeof(df[:,:A])
Out [5]: DataArray{Int64,1} (constructor with 1 method)