[R] levels

[Chris Gordon-Smith]

There is an interesting item on stringsAsFactors in this useR! 2020 session:

https://www.youtube.com/watch?v=X_eDHNVceCU&feature=youtu.be

It's about 27 minutes in.

Chris Gordon-Smith

On 15/07/2020 17:16, Marc Schwartz via R-help wrote:
>> On Jul 15, 2020, at 4:31 AM, andy elprama <andy.elprama using gmail.com> wrote:
>>
>> Dear R-users,
>>
>> Something strange happened within the command "levels"
>>
>> R version 3.6.1
>> name <- c("a","b","c")
>> values <- c(1,2,3)
>> data <- data.frame(name,values)
>> levels(data$name)
>> [1] "a" "b" "c"
>>
>> R version 4.0
>> name <- c("a","b","c")
>> values <- c(1,2,3)
>> data <- data.frame(name,values)
>> levels(data$name)
>> [1] NULL
>>
>> What is happening here?
>
> Hi,
>
> The default value for 'stringsAsFactors' for data.frame() and read.table() changed from TRUE to FALSE in version 4.0.0, per the news() file:
>
> "R now uses a stringsAsFactors = FALSE default, and hence by default no longer converts strings to factors in calls to data.frame() and read.table()."
>
>
> Using 4.0.2:
>
> data <- data.frame(name, values, stringsAsFactors = TRUE)
>
>> levels(data$name)
> [1] "a" "b" "c"
>
>
> If you see behavioral changes from one version of R to another, especially major version increments, check the news() file.
>
> Regards,
>
> Marc Schwartz
>
>   
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