Handling Errors Formatting

1. Handling ErrorsFormatting 3 March 2011

2. Selecting from a list • CHOOSE • Index and list of options • Example: alternative to grade translation

3. Two types of errors • Input errors • Will look at case sensitive and extra blanks when we look at strings • For now, worry about content only • Errors in computation • USUALLY from bad input • BUT sometimes other cases

4. Handling Errors • Do not want Excel error messages But do not want to ignore errors Use built-in functions to be more friendly • Error checking makes expressions complex But do not want to require perfect input Options: • Check and convert • Hide columns or use separate spreadsheets and only change at last step

5. Available Tools • ISERROR and ISERR Checks if a cell has an error • IFERROR Simple form of IF(ISERROR,,) Simple computation: just use it Complex computation: hide column • Translating their errors ERROR.TYPE CHOOSE =CHOOSE(ERROR.TYPE(C2),"NULL","DIV","VAL","REF","NAME")

6. Formatting • Conditional Formatting • Cell Styles are short hands • Alignment options • Page Layout • Setup • Sheet options