Instructions $\frac{3}{3}$

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Create a variable called filter$\_$criteria to select the appropriate rows from the merged table so that you can sum the rides column.

The previous output can be found in the Shell tab.

# Merge the ridership, cal, and stations tables

ridership$\_$cal$\_$stations $=$ ridership.merge $,$

on$=[\text{'}$year$\text{'},$ 'month', 'day'$])$

$.$merge$($stations$,$

on$=$'station$\_$id$\text{'})$

# Create a filter to filter

ridership$\_$cal$\_$stations

filter$\_$criteria $=$

$(($ridership$\_$cal$\_$stations$[\text{'}$month$\text{'}]==$

&

$($ridership$\_$cal$\_$stations$[\text{'}$day$\_$type' $]==$

&

$($ridership$\_$cal$\_$stations$[\text{'}$station$\_$name'$]==$

$)$

# Use $.$ loc and the filter to select for rides

print$($ridership$\_$cal$\_$stations.loc$[$filter$\_$criteria

'rides'$].$sum$())$