Lecture 12

Table examples

DATA 8

Spring 2019

Slides created by John DeNero (denero@berkeley.edu) and Ani Adhikari (adhikari@berkeley.edu)

Announcements

Combining Table Methods

Important Table Methods

t.select(column, …) or t.drop(column, …)

t.take([row, …]) or t.exclude([row, …])

t.sort(column, descending=False, distinct=False)

t.where(column, are.condition(...))

t.apply(function, column, …)

t.group(column) or t.group(column, function)

t.group([column, …]) or t.group([column, …], function)

t.pivot(cols, rows) or t.pivot(cols, rows, vals, function)

t.join(column, other_table, other_table_column)

http://data8.org/datascience/tables.html

Bikes

(Demo)

Maps

(Demo)

Maps

A table containing columns of latitude and longitude values can be used to generate a map of markers

Applies to all features:

color='blue'

size=200

_______.map_table(table, ...)

Either Marker or Circle

Column 0: latitudes

Column 1: longitudes

Column 2: labels

Column 3: colors

Column 4: sizes

Review

Spring 2016 Midterm, Q2(b)

• The name of the station where the most rentals ended (assume no ties).
• The number of stations for which the average duration ending at that station was more than 10 minutes.

(Demo)

Advanced Where (Optional)

Comparison Operators

The result of a comparison expression is a bool value

​

x = 2 y = 3

​

x > 1 x > y y >= 3

​

x == y x != 2 2 < x < 5

(Demo)

t.where(array_of_bool_values) returns a table with only the rows of t for which the corresponding bool is True.