Python – filtering list of strings based on multiple conditions

December 14, 2021

I’m looking to filter a list of strings based on multiple conditions. Adding the output to a new list.

list1 = ['Bike', 'Street Bike', 'Custom Bike', 'Custom Street Bike', 'City Bike', 
'Cruiser Street Bike']

list2 = []

For the purposes of this example, I would like to extract the list items containing ‘Street’ & ‘Bike’

I’ve tried the following method but it is returning all items on the list

list2 = [s for s in list1 if 'Street' and 'Bike' in s]

Expected output

   print(list2)  
   ['Street Bike', 'Custom Street Bike', 'Cruiser Street Bike']

>Solution :

The expression if 'Street' and 'Bike' in s evaluates to True all the time because what it is saying is: if 'Street', which is always True because 'Street' is Truthy. and 'Bike' in s which is also always True because ‘Bike’ is in all items in the list. So you need