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Often, the data that we work with will
not be just in one single data frame,

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it will be spread across
multiple data frames.

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And our job is often to take
these different data frames, and

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combine them together, and
somehow produce a new result.

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Sometimes we're lucky and these data
frames have clearly related information,

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and other times it's a bit of a challenge
to figure out how to relate the rows.

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If the labels match between the data
frames, it's possible to join the two

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together quite easily, much like you would
see in SQL with primary and foreign keys.

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And, of course,
sometimes it's not that cut and dry,

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you have to do some work to
relate the data frames together.

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But that's okay.

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We're ready for that work.

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We've been picking up
manipulation skills so

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that we can get things together
in the right shape for our needs.

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After your data friends
are merged together,

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some new problems will most likely
enter the introduce themselves.

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You might have to worry about
duplicate records or missing data.

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Let's do some merging and

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cleaning up of those problems
that you're bound to run into,