Limiting the number of decimals in a dataframe (R)

A dplyr solution using mutate_if to check if the columns in the current data frame are numeric then apply the round() function to them

# install.packages('dplyr', dependencies = TRUE)
library(dplyr)

DF %>% 
  mutate_if(is.numeric, round, digits = 8)
#>   NE001358.Log.R.Ratio
#> 1          -0.09703693
#> 2           0.13189355
#> 3           0.06292665
#> 4           0.29955913
#> 5          -0.01288043
#> 6           0.06397440
#> 7           0.02716694
#> 8           0.32239536
#> 9           0.17959129

### dplyr v1.0.0+
DF %>% 
  mutate(across(where(is.numeric), ~ round(., digits = 8)))
#>   NE001358.Log.R.Ratio
#> 1            -0.097037
#> 2             0.131894
#> 3             0.062927
#> 4             0.299559
#> 5            -0.012880
#> 6             0.063974
#> 7             0.027167
#> 8             0.322395
#> 9             0.179591

^{Created on 2019-03-17 by the reprex package (v0.2.1.9000)}

Here is.num is TRUE for numeric columns and FALSE otherwise. We then apply round to the numeric columns:

is.num <- sapply(DF, is.numeric)
DF[is.num] <- lapply(DF[is.num], round, 8)

If what you meant was not that you need to change the data frame but just that you want to display the data frame to 8 digits then it's just:

print(DF, digits = 8)

In dplyr 1.0.0 and later one can use across within mutate like this:

library(dplyr)
DF %>% mutate(across(where(is.numeric), ~ round(., 8)))