How to convert all column data type to numeric and character dynamically?

Question

I convert my columns data type manually:

data[,\'particles\'] <- as.numeric(as.character(data[,\'particles\']))

This not ideal as the da

Answer 1

If you don't know which columns need to be converted beforehand, you can extract that info from your dataframe as follows:

vec <- sapply(dat, is.factor)

which gives:

> vec
particles  humidity timestamp      date 
     TRUE      TRUE     FALSE     FALSE 

You can then use this vector to do the conversion on the subset with lapply:

# notation option one:
dat[, vec] <- lapply(dat[, vec], function(x) as.numeric(as.character(x)))
# notation option two:
dat[vec] <- lapply(dat[vec], function(x) as.numeric(as.character(x)))

If you want to detect both factor and character columns, you can use:

sapply(dat, function(x) is.factor(x)|is.character(x))