To allow only values that contain a specific text string, you can use data validation with a custom formula based on the FIND and ISNUMBER functions.
In the example shown, the data validation applied to C5:C9 is:
=...

To lookup the latest file version in a list, you can use a formula based on the LOOKUP function together with the ISNUMBER and FIND functions. In the example shown, the formula in cell G7 is:
=LOOKUP(2,1/(ISNUMBER(...

To extract a word that contains specific text,you can use a formula based on several functions, including TRIM, LEFT, SUBSTITUTE, MID, MAX, and REPT. You can use this formula to extract things like email addresses, or...

If you have worksheet that contains text dimensions (i.e. "50 ft x 200 ft" etc.) you can split the into two parts with formulas that use several text functions.
Background
A common annoyance with data is that it may...

If you need extract the first name from a full name, you can easily do so with the FIND and LEFT functions. In the generic form of the formula (above), name is a full name, with a space separating the first name from...

To count the number of cells that contain certain text, you can use the COUNTIF function. In the generic form of the formula (above), rng is a range of cells, txt represents the text that cells should contain, and "*"...

If you have a list of things (words, substrings, etc) and want to find out which of these things appear in a cell, you can build a simple table and use a formula based on the SEARCH function.
Setup
Suppose you have a...

If you need extract the last name from a full name, you can do so with this rather complex formula that uses several functions. In the generic form of the formula (above), name is a full name, with a space separating...

If you want to get the workbook path (directory) only, you can do so with a formula that uses the LEFT and the FIND function. The result will look something like this:
Drive:\path\to\file\ //Windows
Drive:path:to:...

If you need to extract the first word from some text you can use a formula that uses the FIND and LEFT functions. From the example, the formula looks like this:
=LEFT(B4,FIND(" ",B4)-1)
How this formula...

To separate text and numbers, you can use a formula based on the FIND function, the MIN function, and the LEN function with the LEFT or RIGHT function, depending on whether you want to extract the text or the number. In...

If you want to get the current workbook's full name and path without a sheet name, you can use a formula that employs several text functions to strip off the sheet name. The final result will be a text string that looks...

If want to extract the domain from an email address, you can do so with a formula that uses the RIGHT, LEN, and FIND functions. In the generic form above, email represents the email address you are working with.
In the...

To find the nth occurence of a character in a text string, you can use a formula based on the FIND and SUBSTITUTE functions.
In the example shown, the formula in D5 is:
=FIND(CHAR(160),SUBSTITUTE(B5,"@",...

Note: Excel contains many built-in "presets" for highlighting values with conditional formatting, including a preset to highlight cells that contain specific text. However, if you want more flexibility, you can use your...