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[MUSIC]

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Hi, I'm Rachel,
a Python teacher here at Treehouse.

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If you're a programmer,
you're going to have to deal with dates or

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times eventually, and sometimes,
even at the same time.

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Now, computers think about time a little
differently than we do as humans, so

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it's our job as programmers to have
an understanding of that before we start

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creating programs that deal with date or
time.

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There are two main methods that
computers use to keep time.

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And you'll likely encounter both in your
journey as a programmer depending on

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what you do.

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These are UTC time and the Unix timestamp.

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UTC stands for
Coordinated Universal Time and

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it's basically the global standard for
timekeeping.

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You may even know it as
Greenwich Mean Time.

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Imagine it as the official
time that everyone agrees on.

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You know how you've often seen your
time zone written as GMT+9 or GMT- 7?

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Well, this is GMT+0, or GMT or simply UTC.

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It's often used as a reference point
because it doesn't change with daylight

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saving or time zone.

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Programmers often default to UTC to
avoid issues with time zones and

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UTC is used if you schedule cron jobs.

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Some other use cases are in aviation,
weather forecasts, and

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even in the International Space Station.

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The Unix timestamp is
a computer's way of telling time.

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Picture a starting point,
called the Unix epoch,

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set on January 1, 1970, 00:00:00 UTC.

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A Unix timestamp is just the count of
seconds that have passed since that epoch.

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This timestamp idea helps computers
handle time consistently,

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no matter where they are in the world.

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So when you see a Unix
timestamp like 1627892167

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it means that that's how many
seconds have elapsed since

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that specific point in time,
January 1 1970.

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Some use cases are storing
timestamps in MySQL or

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PostgreSQL, file timestamps
in Unix systems,

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timestamps in archive file
formats like RAR and TAR, and

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Discord's own dynamic timestamp
uses the Unix timestamp.

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Now, all this seems well and good, but
it would be a little tricky to have

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to convert our thinking
into Unix timestamps or

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UTC every time we worked with dates or
times.

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And what if you just wanted
to work with a time of day or

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a day without worrying about the time?

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Luckily, Python comes with a set of really
solid tools for dealing with dates and

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times.