Converting "-" to a "0" in R

Question

I have a column Apps in dataframe dframe

that looks like this:

I need the column to be type int instead of String so I need to convert the 5th row to a 0.

How did you read this data into R? It probably would have been a good idea to use `read.table(..., na.strings="-")` to read it in as missing from the beginning. — MrFlick, Dec 14 '18 at 21:23
`dframe$Apps[ dframe$Apps == "-" ] <- "0"`? I agree with MrFlick, though, as a value of "0" is not the same as the hyphen, which many programs (not R) interpret as "not a valid number". I'm guessing that as it is now, it is `character`. Use the `na.strings=` argument, it is very worth it to you to read it in correctly the first time and allow `read.table` to handle the column classes for you. It is not perfect, but anything else suggests something else is wrong with your data. (BTW: `dframe$Apps <- as.numeric(dframe$Apps)` might suffice for you.) — r2evans, Dec 14 '18 at 21:25

score 3 · Answer 1 · answered Dec 14 '18 at 21:31

3

dframe$Apps[dframe$Apps == "-"] <- "0"
dframe$Apps <- as.integer(dframe$Apps)

answered Dec 14 '18 at 21:31

Max Ghenis

score 0 · Answer 2 · answered Dec 14 '18 at 22:42

You can do it with ifelse and the tidyverse approach:

require(tidyverse)

df %>% 
  mutate(Apps = ifelse(Apps == "-", 0, Apps))

  Apps
1    4
2    3
3    2
4    5
5    0

Dataset:

df <- read.table(text = "    Apps
1    31
2    12
3    10
4    33
5    -", header = TRUE)

score 0 · Answer 3 · answered Dec 14 '18 at 23:07

0

dframe$Apps <- as.integer(gsub("-", "0", dframe$Apps, fixed = TRUE))

will give you an integer column as I suspect you want.

answered Dec 14 '18 at 23:07

3 Answers3