How to convert all characters of a data frame to Numeric

```
char_columns<-sapply(merged_data, is.character) #identify character columns
data_char_num<-merged_data #replicate data
data_char_num[,char_columns]<-as.data.frame(apply(data_char_num[,char_columns],2, as.numeric))#recode character as numeric
sapply(data_char_num, class) #print classes of all columns
```