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how to remove factors from whole dataframe?

Jim Lemon

Sun, Sep 19, 2021 4:12 AM

Hi Luigi,
Okay, so you mean:
I want to change all factors in a dataframe to character class, _not_
remove them.

factor2character<-function(x) if(is.factor(x)) return(as.character(x))
else return(x)
df1<-lapply(df,factor2character)

Jim

On Sun, Sep 19, 2021 at 8:03 PM Luigi Marongiu <marongiu.luigi at gmail.com> wrote:

Thank you Jim, but I obtain:
```

str(df)

'data.frame': 5 obs. of  3 variables:
 $ region : Factor w/ 5 levels "A","B","C","D",..: 1 2 3 4 5
 $ sales  : num  13 16 22 27 34
 $ country: Factor w/ 5 levels "a","b","c","d",..: 1 2 3 4 5

df1<-df[,!unlist(lapply(df,is.factor))]
str(df1)

 num [1:5] 13 16 22 27 34

df1

[1] 13 16 22 27 34
```
I was expecting
```
str(df)
'data.frame': 5 obs. of  3 variables:
 $ region : char "A","B","C","D",..: 1 2 3 4 5
 $ sales  : num  13 16 22 27 34
 $ country: char "a","b","c","d",..: 1 2 3 4 5
```

On Sun, Sep 19, 2021 at 11:37 AM Jim Lemon <drjimlemon at gmail.com> wrote:

Hi Luigi,
It's easy:

df1<-df[,!unlist(lapply(df,is.factor))]

_except_ when there is only one column left, as in your example. In
that case, you will have to coerce the resulting vector back into a
one column data frame.

Jim

On Sun, Sep 19, 2021 at 6:18 PM Luigi Marongiu <marongiu.luigi at gmail.com> wrote:

Hello,
I woul dlike to remove factors from all the columns of a dataframe.
I can do it n a column at the time with
```

df <- data.frame(region=factor(c('A', 'B', 'C', 'D', 'E')),
                 sales = c(13, 16, 22, 27, 34), country=factor(c('a',
'b', 'c', 'd', 'e')))

new_df$region <- droplevels(new_df$region)
```

What is the syntax to remove all factors at once (from all columns)?
For this does not work:
```

str(df)

'data.frame': 5 obs. of  3 variables:
 $ region : Factor w/ 5 levels "A","B","C","D",..: 1 2 3 4 5
 $ sales  : num  13 16 22 27 34
 $ country: Factor w/ 5 levels "a","b","c","d",..: 1 2 3 4 5

df = droplevels(df)
str(df)

'data.frame': 5 obs. of  3 variables:
 $ region : Factor w/ 5 levels "A","B","C","D",..: 1 2 3 4 5
 $ sales  : num  13 16 22 27 34
 $ country: Factor w/ 5 levels "a","b","c","d",..: 1 2 3 4 5
```
Thank you

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Thread (13 messages)

Luigi Marongiu how to remove factors from whole dataframe? Sep 19 Rolf Turner how to remove factors from whole dataframe? Sep 19 Jim Lemon how to remove factors from whole dataframe? Sep 19 Luigi Marongiu how to remove factors from whole dataframe? Sep 19 Fabio D'Agostino how to remove factors from whole dataframe? Sep 19 Jim Lemon how to remove factors from whole dataframe? Sep 19 Luigi Marongiu how to remove factors from whole dataframe? Sep 19 Rui Barradas how to remove factors from whole dataframe? Sep 19 Luigi Marongiu how to remove factors from whole dataframe? Sep 19 Avi Gross how to remove factors from whole dataframe? Sep 19 Bert Gunter how to remove factors from whole dataframe? Sep 19 Avi Gross how to remove factors from whole dataframe? Sep 19 Bert Gunter how to remove factors from whole dataframe? Sep 19