List Slices
A list slice is a subset of an existing list. That is, it's a smaller
list made from a bigger list. We can create a list slice easily with
the following syntax:
list[start:stop]
Please note that when taking a slice of a list the slice only includes
indices that are less than the stop index. Here is a short example of
some various ways to make slices:
players = ['lionel messi', 'euler', 'pelé', 'gauss', 'cristiano ronaldo', 'goat']
# Create a slice of the first 2 players.
players[0:2]
# Create a slice from the beginning of the list to index 3
print(players[:4])
# Create a slice starting from index 1 to the end of the list.
print(players[1:])
['lionel messi', 'euler']
['lionel messi', 'euler', 'pelé']
Looping Through a Slice
You can loop through a slice and apply the usual methods on them as
shown below:
players = ['lionel messi', 'euler', 'pelé', 'gauss', 'cristiano ronaldo', 'goat']
# Print the first three players in the list in their own line
for player in players[:3]:
print(player.title())
Lionel Messi
Euler
Pelé
Copying a List
There are times when you want to make an exact copy of a list and
start modifying the new list. An example is if you make a website that
lets people list their favorite G.O.A.T soccer players and it lets you
copy someone else's list and modify it to your liking.
players = ['lionel messi', 'euler', 'pelé', 'gauss', 'cristiano ronaldo', 'goat']
# Copy the players list
my_players = players[:]
# Print the Lists:
print("My friend's favorite players are:")
print(players)
print("My favorite players are:")
print(my_players)
My friend's favorite players are:
['lionel messi', 'euler', 'pelé', 'gauss', 'cristiano ronaldo', 'goat']
My favorite players are:
['lionel messi', 'euler', 'pelé', 'gauss', 'cristiano ronaldo', 'goat']
We can use any of the methods we've learned to change the lists
independently.
players = ['lionel messi', 'euler', 'pelé', 'gauss', 'cristiano ronaldo', 'goat']
# Copy the players list
my_players = players[:]
# Add a new player to your friend's list:
players.append('mbappe')
# Add a new player to your own list:
my_players.append('mario gotze')
# Print the Lists:
print("My friend's favorite players are:")
print(players)
print("My favorite players are:")
print(my_players)
My friend's favorite players are:
['lionel messi', 'euler', 'pelé', 'gauss', 'cristiano ronaldo', 'goat', 'mbappe']
My favorite players are:
['lionel messi', 'euler', 'pelé', 'gauss', 'cristiano ronaldo', 'goat', 'mario gotze']
