Answer:
To display the symbol, security, and founded for companies that are missing data for 'date first added', you can use the following code:
stocks %>%
select(symbol, security, founded) %>%
filter(isna(date_first_added))
This code uses the isna() function to identify rows in the stocks data frame where the date_first_added column is missing data. The filter() function is then used to keep only these rows in the resulting data frame. Finally, the select() function is used to select only the symbol, security, and founded columns, and the resulting data frame is displayed.
This code assumes that the stocks data frame has already been loaded and that the symbol, security, founded, and date_first_added columns are present in the data frame. If any of these assumptions is not true, the code may not work as expected.
In summary, using the isna() and filter() functions, you can display the symbol, security, and founded for companies that are missing data for 'date first added' in the stocks data frame. This can help you to identify which companies have incomplete data and take appropriate action, such as contacting the companies or excluding them from further analysis.