tidyr :: unite丢弃小数0

Question

I want to combine numbers from two and two columns within a data frame (values in the columns are the upper and lower values for confidence intervals in statistical analysis).

My perferred method would be to use tidyr and the unite function. But take 0.20 as an example, that number will be modified to 0.2, ie these last decimals in numbers are dropped if they are equal to zero. Is there any way to keep the original format when using unite ?

unite is describe here: https://www.rdocumentation.org/packages/tidyr/versions/0.8.2/topics/unite

Example:

# Dataframe
df <-  structure(list(est = c(0.05, -0.16, -0.02, 0, -0.11, 0.15, -0.26, 
-0.23), low2.5 = c(0.01, -0.2, -0.05, -0.03, -0.2, 0.1, -0.3, 
-0.28), up2.5 = c(0.09, -0.12, 0, 0.04, -0.01, 0.2, -0.22, -0.17
)), row.names = c(NA, 8L), class = "data.frame")

Combining (uniting) columns for confidence with unite , using a comma as a separator

library(tidyr)
df <- unite(df, "CI", c("low2.5", "up2.5"), sep = ", ", remove=T)

gives

df
    est           CI
1  0.05   0.01, 0.09
2 -0.16  -0.2, -0.12
3 -0.02     -0.05, 0
4  0.00  -0.03, 0.04
5 -0.11  -0.2, -0.01
6  0.15     0.1, 0.2
7 -0.26  -0.3, -0.22
8 -0.23 -0.28, -0.17

I would want this:

    est           CI
1  0.05   0.01, 0.09
2 -0.16  -0.20, -0.12
3 -0.02  -0.05, 0.00
4  0.00  -0.03, 0.04
5 -0.11  -0.20, -0.01
6  0.15   0.10, 0.20
7 -0.26  -0.30, -0.22
8 -0.23  -0.28, -0.17

I believing doing this with Base R will be complicated (having to move/rearrange the many combined columns and delete the old columns). Is there any way to avoid unite from dropping decimals with the value of zero?

Answer 1

This works:

library(tidyverse)

df %>% 
  mutate_if(is.numeric, ~format(., nsmall = 2)) %>% 
  unite("CI", c("low2.5", "up2.5"), sep = ", ", remove=T)
#    est           CI
#1  0.05  0.01,  0.09
#2 -0.16 -0.20, -0.12
#3 -0.02 -0.05,  0.00
#4  0.00 -0.03,  0.04
#5 -0.11 -0.20, -0.01
#6  0.15  0.10,  0.20
#7 -0.26 -0.30, -0.22
#8 -0.23 -0.28, -0.17