You will find flash fill functionality under data menu and there in a data tool box.

The icon has a flash in top left hand corner.

An example demonstrates how flash fill works.

In the B-column you have a list data. In the C-column you should take the digits after 123_. The C5 should hold value dr43 and so on.

Activate the C4 and press flash fill.

That saved some time.

When you press flash fill options, you will get following parameters.

Undo simply removes what flash fill just filled. Accept suggestion simply fixes the new values and the option box disappears. Select all 4 changed cells activates the cells C5:C8.

Another example is if you want to round down the numbers with several decimals. Just enter 423 manually into D3 and press flash fill.

Press flash fill.

The results are correct.

The same results can be achieved by ROUNDDOWN.

You have list of names.

You should create email addresses based on first name and last name. In D2 there is an example. Note that D2 needs be a static value not a formula.

Place the cursor in D2 and press flash fill.

It is difficult to find out all the examples when flash fill could be useful. In case you face a situation that you need to create a new column based on another column, just don’t forget flash fill. It might be useful.