Python Data Visualization Transcripts
Chapter: Altair
Lecture: Data type

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0:00 In the very beginning of this course, one of the core concepts we talked about were the different data types and how they
0:06 can be used in data visualization. So hopefully you recall that as you were looking at some of these altair examples but
0:13 I'll summarize them here because it is hard to keep them straight and this can be
0:17 another useful reference for you. So the first type of data type is a quantitative type that we can use the shorthand code Q.
0:25 And this is for for a continuous numerical value. An ordinal value is discreet. So think of a categorical variable. There is an order amount to it.
0:35 A nominal value is a discreet as well but it is a un ordered. So in this example colors red,
0:42 yellow, green or countries could be good examples of nominal values, temporal is a time
0:48 or a date value. GeoJson is also used for geographic plotting but we will not cover that in this course.
0:54 So the important thing to keep in mind is that when you were working with pandas
0:57 altair will infer what the type is based on a couple different lookups. So if it is numeric, it will assign a quantitative variable to it.
1:07 If it is a date or time type it will be temporal and a string will be assigned to a nominal value.
1:16 So this gives you hopefully a really useful table as you use altair and play around with different data types for your visualizations.

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