To count cells that do not contain many different strings, you can use a rather complex formula based on the MMULT function. In the example shown, the formula in F5 is:
{=SUM(1-(MMULT(--(ISNUMBER(SEARCH(TRANSPOSE(...

To filter a data in an array formula (to exclude or require certain values), you can use an array formula based on the IF, MATCH, and ISNUMBER functions.
In the example shown, the formula in H5:
{=COUNT(IF(ISNUMBER(...

To test a range for numbers, you can use a formula based on the ISNUMBER and SUMPRODUCT functions.
In the example shown, the formula in xxxx is:
=SUMPRODUCT(--ISNUMBER(C5:C9))>0
How this formula works
Working...

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 "*"...

To extract all matches based on a partial match, you can use use an array formula based on the INDEX and AGGREGATE functions, with support from ISNUMBER and SEARCH. In the example shown, the formula in G5 is:
=IF(F5...

To highlight cells that contain one of many text strings, you can use a formula based on the functions ISNUMBER and SEARCH, together with the SUMPRODUCT function. In the example shown, the conditional formatting applied...

To check a cell for one of several things, and return the first match found in the list, you can use an INDEX / MATCH formula that uses SEARCH or FIND to locate a match. In the example shown, the formula in C5 is:
{=...

To categorize text using keywords with a "contains" match, you can use the SEARCH function, with help from INDEX and MATCH. In the example shown, the formula in C5 is:
{=INDEX(categories,MATCH(TRUE,ISNUMBER(SEARCH(...

Note: these is an experimental formula that uses a hard coded array constant, set down here for reference and comment. Casually tested only, so take care if you use or adapt.
Sometimes you encounter data that mixes...

To test a cell for one of several things, and return a custom result for the first match found, you can use an INDEX / MATCH formula based on the SEARCH function.
In the example shown, the formula in C5 is:
{=INDEX(...

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:
=...

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...

To check if a cell contains specific text, you can use the SEARCH function together with the ISNUMBER function. In the generic version, substring is the specific text you are looking for, and text represents text in the...

To sum if cells contain either one text string or another (i.e. contain "cat" or "rat") you can use the SUMPRODUCT function.
Background
When you sum cells with "OR" criteria, you need to be careful not to double count...

To count cells that contain either one value or another, you an either use a helper column then tally up the count, or a more complex single cell formula.
Background
When you count cells with "OR" criteria, you need...