Adding a row based on conditional count of rows in R / dplyr-CodePudding

I'm web-scraping a data frame that is typically 1 column and 8 rows. Sometimes the data frame is missing one observation (row 6). As such, my variables get out of order while scraping (7 becomes 6, 8 becomes 7) and cascades to cause other problems.

I have a solution to this problem when row 6 is missing. I'm using add_row to add a placeholder row that ends up with a value of 'NA' (exactly what I want).

#Data frame with missing value
 value <- c(10, 43, 67, 89, 05, 28, 99)
  df <- data.frame(value)

#Solving the problem
  df2<-df %>% add_row(value=NA,.before=6)

My question is - is there a way to add_row conditionally? If there is less than 8 rows, add the missing row, or else do nothing?

Thanks.

CodePudding user response：

This should do the job


if(length(df$value) != 8){
df[0:length(df$value) 1,"value"] <- c(df$value[1:5], NA, df$value[6:length(df$value)])
}

CodePudding user response：

Here's one way -

value <- c(10, 43, 67, 89, 05, 28, 99)

if(length(value) == 7) {
  value <- append(value, NA_integer_, after = 5)
}

df <- data.frame(value)

One way with dplyr -

tibble(value) %>%
  {if(nrow(.) == 7) add_row(., value = NA_integer_, .after = 5) else .}

# A tibble: 8 × 1
  value
  <dbl>
1    10
2    43
3    67
4    89
5     5
6    NA
7    28
8    99