I have a data frame and columns are different classes including strings, numeric, integer, etc.

I have a vector of classes `class_vector <- c("string", "integer" ,"numeric" , "logical" )` that I need to use to coerce each column class to.

Sample data frame:

```
df <- data.frame(letters = letters[sample.int(20, 10)], integers = sample.int(100, 10), 
                 numbers = rnorm(10), logical = sample.int(2, 10, replace = T)-1)

```

I've tried different variations of the apply function, but I have only been successful at changing multiple column classes to one single class (eg. "character"), but I can't seem to use a vector/list to change different columns to different classess.