How do I change values to numeric in r?

Question

Reproducible Sample Data

df <- data.frame(
  change_time = c("[4605]", "[4000]", "[4305]", 
                  "[5530]", "[6500]", "[5653]", 
                  "[2936]", "[4691]", "[2500]")
)

data frame with values

Hi, how do I change values to numeric? so far I've used as.numeric(), but I get the warning Warning message: NAs introduced by coercion

Answer 1

when dealing with R object, it is wise to use str() function to see what data types your are having. I'm not sure, but I'm assume that your data is a stringwith [ ] in each side.

 #Install from tidyverse or manually
library(magrittr)
library(stringr)
str_extract(df$change_time,"\\d*") %>% as.numeric()

Answer 2

Here is a solution using the dplyr and stringr packages. mutate allows you to modify the existing change_time variable. str_remove_all is used to remove the matches pattern in the change_time variable. as.numeric converts the change_time variable from character to numeric .

Replace df with the name of your dataset.

# Recreate sample data 

df <- data.frame(
  change_time = c("[4605]", "[4000]", "[4305]", "[5530]", "[6500]", "[5653]", "[2936]", "[4691]", "[2500]")
)

# Import the libraries

library(dplyr)
library(stringr)

# Code to accomplish what is asked

df %>% 
  mutate(
    change_time = as.numeric(str_remove_all(change_time, "\\[|\\]"))
    )

# Output

#>   change_time
#> 1        4605
#> 2        4000
#> 3        4305
#> 4        5530
#> 5        6500
#> 6        5653
#> 7        2936
#> 8        4691
#> 9        2500

^{Created on 2021-03-11 by the reprex package (v0.3.0)}