Following up on the changes in DataFrames Johan mentioned:
The biggest difference I have found in DataFrames for Julia 0.3 is the
absence of the matrix() function. How can I quickly convert a DataFrame or
DataArray into an Array without matrix()? Here's an example of the issue:
*Setup:*
julia> X
3x3 DataFrame
|-------|------|-----|-----|
| Row # | x1 | x2 | x3 |
| 1 | -1.0 | 0.0 | 1.0 |
| 2 | 2.0 | 3.0 | 4.0 |
| 3 | 5.0 | 6.0 | 7.0 |
julia> y
3-element DataArray{Float64,1}:
1.0
0.0
1.0
*Issue:*
julia> linreg(X,y)
ERROR: `linreg` has no method matching linreg(::DataFrame,
::DataArray{Float64,1})
*Old Solution:*
julia> linreg(matrix(X),vec(matrix(y')))
4-element Array{Float64,1}:
0.222222
-0.222222
1.38778e-16
0.222222
But matrix doesn't exist anymore. So I'm looking for commands that do the
following:
*(1) Convert DataArray{Float64,1} into Array{Float64,1}.(2) Convert
DataFrame into Array{Float64,2}.*
How do you do this in Julia 0.3?
Thanks,
Bradley
On Monday, August 18, 2014 11:39:45 AM UTC-5, Johan Sigfrids wrote:
>
> There are probably going to be quite a few changes in the DataFrames
> package when you go from Julia 0.2 to 0.3.
>
> On Monday, August 18, 2014 7:28:48 PM UTC+3, Bradley Setzler wrote:
>>
>> Thanks, Johan. I have upgraded to 0.3 release candidate and see what you
>> mean about scalar multiplication not working for DataFrame any more. I see
>> also that DataArray successfully converts Integer to Float in the way John
>> was describing earlier, which solves the original problem.
>>
>> Problem solved, thanks guys,
>> Bradley
>>
>>
>>
>> On Monday, August 18, 2014 10:32:25 AM UTC-5, Johan Sigfrids wrote:
>>>
>>> Multiplying a DataFrame by a scalar has been deprecated and will not
>>> work once you update to Julia 0.3 and the associated DataFrames version.
>>>
>>> On Monday, August 18, 2014 6:10:44 PM UTC+3, Bradley Setzler wrote:
>>>>
>>>> Update: I found a 1-line command to convert everything in a DataFrame
>>>> into a Float that seems to work generally:
>>>>
>>>> data = data*1.0
>>>>
>>>> So, for example,
>>>> julia> A=DataFrame([1 2 ; 3 4])
>>>> 2x2 DataFrame:
>>>> x1 x2
>>>> [1,] 1 2
>>>> [2,] 3 4
>>>> julia> A=A*1.0
>>>> 2x2 DataFrame:
>>>> x1 x2
>>>> [1,] 1.0 2.0
>>>> [2,] 3.0 4.0
>>>>
>>>> Best,
>>>> Bradley
>>>>
>>>>
>>>>
>>>> On Monday, August 18, 2014 10:02:02 AM UTC-5, Bradley Setzler wrote:
>>>>>
>>>>> Hi John,
>>>>>
>>>>> Thanks for your reply, I'm getting the following:
>>>>>
>>>>> julia> A=DataArray([1 2; 3 4])
>>>>> 2x2 DataArray{Int64,2}:
>>>>> 1 2
>>>>> 3 4
>>>>> julia> A*.5
>>>>> 2x2 DataArray{Float64,2}:
>>>>> 0.5 1.0
>>>>> 1.5 2.0
>>>>>
>>>>> julia> A/2.
>>>>> 2x2 DataArray{Float64,2}:
>>>>> 0.5 1.0
>>>>> 1.5 2.0
>>>>> julia> A/2
>>>>> InexactError()
>>>>>
>>>>>
>>>>> So it converts to Float if divided by Float, but does not convert if
>>>>> divided by Integer.
>>>>>
>>>>> Best,
>>>>> Bradley
>>>>>
>>>>>
>>>>>
>>>>> On Monday, August 18, 2014 9:31:43 AM UTC-5, John Myles White wrote:
>>>>>>
>>>>>> Hi Bradley,
>>>>>>
>>>>>> Would you consider using DataArrays for this? DataFrames no longer
>>>>>> support these operations, so any upgrade in your setup would turn all of
>>>>>> this code into errors.
>>>>>>
>>>>>> All of these operations work on DataArrays already.
>>>>>>
>>>>>> — John
>>>>>>
>>>>>> On Aug 18, 2014, at 7:28 AM, Bradley Setzler <[email protected]>
>>>>>> wrote:
>>>>>>
>>>>>> >
>>>>>> >
>>>>>> > Good morning,
>>>>>> >
>>>>>> > I am looking for a simple way to convert an Integer DataFrame to a
>>>>>> Float DataFrame. Here is an example of the problem:
>>>>>> >
>>>>>> > julia> using DataFrames
>>>>>> > julia> A=DataFrame([1 2; 3 4])
>>>>>> > 2x2 DataFrame:
>>>>>> > x1 x2
>>>>>> > [1,] 1 2
>>>>>> > [2,] 3 4
>>>>>> >
>>>>>> > With multiplication, there is no problem automatically converting
>>>>>> to Float:
>>>>>> >
>>>>>> > julia> A*.5
>>>>>> > 2x2 DataFrame:
>>>>>> > x1 x2
>>>>>> > [1,] 0.5 1.0
>>>>>> > [2,] 1.5 2.0
>>>>>> >
>>>>>> > But with division, for example, the conversion fails:
>>>>>> >
>>>>>> > julia> A/2
>>>>>> > InexactError()
>>>>>> >
>>>>>> > Ideally, there would be a one-line command so that we don't have to
>>>>>> worry about this issue, say DataFloat() of the form:
>>>>>> >
>>>>>> > julia> A=DataFloat(A)
>>>>>> > 2x2 DataFrame:
>>>>>> > x1 x2
>>>>>> > [1,] 1.0 2.0
>>>>>> > [2,] 3.0 4.0
>>>>>> >
>>>>>> > Does something like this exist?
>>>>>> >
>>>>>> > Thanks,
>>>>>> > Bradley
>>>>>> >
>>>>>>
>>>>>>
