Conditional title heading depending on output of code block R Markdown

Question

I know this question has been asked before, but I'm still struggling to find an answer that works with my example. Basically, I have this code block that reads the number of rows of a dataframe. If there are any rows in the dataframe, it will output a table using kable(). If there are zero rows, no table is output.

When the table IS output, I would like to have a title heading above the table (just bolded text, i.e. "My Table"). When no table is output, I want no heading. How can I accomplish this? I've tried to use eval statements like print_option in the r setup block but no luck. Here's the stripped-down pseudo-code:

```{r warning = FALSE, echo = FALSE, fig.height=10, fig.width=6}
    
    #Existing data frame my_df

   numRows <- nrow(my_df)

   if (numRows>0) {

       #Print table 
       my_df %>%
       arrange(my_field)%>%
       kable() %>%  kable_styling(bootstrap_options = "striped","condensed", font_size = 12)

   }


```

Answer 1

I made minimal changes to implement your code with the iris dataset and it works as you would like it to.

No rows (and no header)

```{r warning = FALSE, echo = FALSE, fig.height=10, fig.width=6}
library(dplyr)
library(kableExtra)

#Existing data frame my_df
my_df <- iris[NULL, ]
numRows <- nrow(my_df)
```

`r  if (numRows > 0) {"## This is your heading written in markdown"}`

```{r warning = FALSE, echo = FALSE, fig.height=10, fig.width=6}
if (numRows>0) {
  #Print table 
  my_df %>%
    arrange(Species) %>%
    kable() %>%
    kable_styling(bootstrap_options = "striped","condensed", font_size = 12)
}
```

With data (and table header)

```{r warning = FALSE, echo = FALSE, fig.height=10, fig.width=6}
library(dplyr)
library(kableExtra)

#Existing data frame my_df
my_df <- iris[1:10, ]
numRows <- nrow(my_df)
```

`r  if (numRows > 0) {"## This is your heading written in markdown"}`

```{r warning = FALSE, echo = FALSE, fig.height=10, fig.width=6}
if (numRows>0) {
  #Print table 
  my_df %>%
    arrange(Species) %>%
    kable() %>%
    kable_styling(bootstrap_options = "striped","condensed", font_size = 12)
}
```