Sometimes we don’t care exactly WHAT characters are in a text, just that there are SOME characters. Enter the wildcard .
! Wildcards will match any single character (letter, number, symbol or whitespace) in a piece of text. They are useful when we do not care about the specific value of a character, but only that a character exists!
Let’s say we want to match any 9-character piece of text. The regex .........
will completely match orangutan
and marsupial
! Similarly, the regex I ate . bananas
will completely match both I ate 3 bananas
and I ate 8 bananas
!
What happens if we want to match an actual period, .
? We can use the escape character, \
, to escape the wildcard functionality of the .
and match an actual period. The regex Howler monkeys are really lazy\.
will completely match the text Howler monkeys are really lazy.
.
Instructions
The interactive applet in the browser allows you to enter a regular expression and see if it matches a string of text. If a character is matched, you’ll see it highlighted in green. If there’s a checkmark next to the string, you’ve completely matched the whole piece of text!
Enter a regular expression that matches each of the strings listed below “Match these strings” and does NOT match any of the strings listed below “Don’t match these strings.”
When you’ve entered a regular expression that matches the appropriate strings, a key will appear in the browser. Add the key to the end of the URL in the code editor and run the code to unlock the next exercise!