Formula in Excel to count occurrences of substrings within strings

Question

I am trying to count the number of times a sub-string appears within a column of string data in Excel. Please see the below example.

The column of string data (tweet

Answer 1

You are nearly there, use

=COUNTIF(A:A, "*"&B1&"*")

Caveat:
This counts the number of cells in A:A that contain the string one or more times. It does not count the total number of instances of the string.