Add a row to a tibble to sum some, but not all, columns in the tibble

[landonphd]

I honestly don't think that what I want to do is that difficult. However, I've been beating my head against this issue for several hours without finding a solution, so I guess I'll ask for help.

I need to add a new row to a tibble, The newly-added row will contain the sums of some, but not all, of the columns in the tibble.

https://stackoverflow.com/questions/33565949/add-row-to-data-frame-with-dplyr, suggests this code snippet:

"mydata %>%
rbind(list(c("00000", "Region Total", sum(GDP),sum(Percent))))"

However, I receive the error message "Error in xi[[j]] : subscript out of bounds"

Thanks in advance for your help.

---

This is my starting tibble:

	FIPS	County	GDP	Percent
1	29007	Audrain	698358	0.5
2	29019	Boone	7521903	4.5
3	29027	Callaway	1456387	-3.2
4	29029	Camden	1152673	-1.1

---

This is my desired output containing the new row #5, which contains observations for the 2 character variables (FIPS, County) and the sums of the two numeric variables (GDP, Percent):

	FIPS	County	GDP	Percent
1	29007	Audrain	698358	0.5
2	29019	Boone	7521903	4.5
3	29027	Callaway	1456387	-3.2
4	29029	Camden	1152673	-1.1
5	00000	Region Total	10829321	0.7

---

FIPS <- c("29007", "29019", "29027", "29029")
County <- c("Audrain", "Boone", "Callaway", "Camden")
GDP <- c(698358, 7521903, 1456387, 1152673)
Percent <- c(0.5, 4.5, -3.2, -1.1)
mydata <- cbind.data.frame(FIPS, County, GDP, Percent)

mydata <-as_tibble(data)

mydata$FIPS <- as.character(mydata$FIPS)
mydata$County <- as.character(mydata$County)

class(mydata$FIPS)
class(mydata$County)
class(mydata$GDP)
class(mydata$Percent)

# suggested by https://stackoverflow.com/questions/33565949/add-row-to-data-frame-with-dplyr
mydata %>% 
  rbind(list(c("00000", "Region Total", sum(GDP),sum(Percent))))

#error:  Error in xi[[j]] : subscript out of bounds

[FJCC]

The second (as of this writing) answer in that stack overflow thread has a better solution than the accepted answer; using the add_row function of tibble.

library(tibble)
library(magrittr)
FIPS <- c("29007", "29019", "29027", "29029")
County <- c("Audrain", "Boone", "Callaway", "Camden")
GDP <- c(698358, 7521903, 1456387, 1152673)
Percent <- c(0.5, 4.5, -3.2, -1.1)
mydata <- cbind.data.frame(FIPS, County, GDP, Percent)

mydata <- as_tibble(mydata)

mydata$FIPS <- as.character(mydata$FIPS)
mydata$County <- as.character(mydata$County)

class(mydata$FIPS)
class(mydata$County)
class(mydata$GDP)
class(mydata$Percent)

mydata <- mydata %>% 
  add_row(FIPS = "00000", County = "Region Total", 
          GDP = sum(GDP), Percent = sum(Percent))

Frankly, I would not expect the accepted answer in that thread to work. I do not see how the sum function can know that GDP and Percent refer to columns in the mydata tibble. There may be some tibble magic in there that I am unaware of.

[cderv]

@landonphd
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[landonphd]

@FJCC, Thanks for your help.

Your answer was very helpful and gave me the exact result that I wanted.

One of the solutions that I tried before I asked for help applied add_row. Your suggestion helped me to troubleshoot and to fix a different error that I believe was my problem all along. Add_row in my original code apparently wasn't working because an error in a different portion of the code inexplicably changed one of my variables to an object. I can't explain that error, but, after I fixed it, your suggestion for add_row worked like a charm.

I really appreciate your time and suggestion.