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- [Instructor] For this Self
Check exercise we'd like you

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to create your own regular
expression and test it,

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and specifically we wanna
match a simple street address

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consisting of a number
with one or more digits

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followed by two words with
one or more characters each.

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So something like 123
Main Street in this case.

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So go ahead and pause the
video and give that a shot,

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and then come back to see the answer.

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Okay, let's go ahead and give this a shot.

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So first we have to import
the regular expression module.

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Here is the regular expression.

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So we've got a digit character class

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that's saying one or more digits.

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So the plus quantifier says one or more

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of the preceding sub expression,

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and that sub expression
is a character class.

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Followed by a space, which
is a literal character.

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Then we have two words,

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and in our case we solved it saying

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that we specifically
wanted a word starting

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with an uppercase letter followed

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by zero or more lowercase
letters and then a space.

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And then again another word
with an uppercase letter

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and zero or more lowercase letters.

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So let's go ahead and define
that regular expression,

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and then we'll go ahead and test it

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with the 123 Main Street string
that we defined up above.

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And of course this is a very primitive

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regular expression for matching addresses,

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because addresses can certainly
take many other forms.

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But here we're going to
use the regular expression

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we specified as a raw string.

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We'll pass that in as the first argument.

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The string we're trying to match
against is 123 Main Street.

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And when I go ahead and
execute that, we have a match.

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On the other hand, if we remove
the number at the beginning

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and try to use that
same regular expression,

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we get a no match result in that case

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because it's missing a key part,

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the required one or more
digits followed by a space

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in your original regular expression.

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So again these can get
much more complicated

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than what I'm showing you here,
but we're just introducing

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some of the fundamental
capabilities of regular expressions.