Lists
A list stores many values in a single structure.
T = [27.3, 27.5, 27.7, 27.5, 27.6] # array of temperature measurements
print('temperature:', T)
print('length:', len(T))
print('zeroth item of T is', T[0])
print('fourth item of T is', T[4])
T[0] = 21.3
print('temperature is now:', T)
primes = [2, 3, 5]
print('primes is initially', primes)
primes.append(7) # append at the end
primes.append(11)
print('primes has become', primes)
print('primes before', primes)
del primes[4] # remove element #4
print('primes after', primes)
a = [] # start with an empty list
a.append('Vancouver')
a.append('Toronto')
a.append('Kelowna')
print(a)
a[99] # will give an error message (past the end of the array)
a[-1] # display the last element; what's the other way?
a[:] # will display all elements
a[1:] # starting from #1
a[:1] # ending with but not including #1
Lists can be heterogeneous and nested:
a = [11, 21, 31]
b = ['Mercury', 'Venus', 'Earth']
c = 'hello'
nestedList = [a, b, c]
print(nestedList)
You can search inside a list:
'Venus' in b # returns True
'Mars' in b # returns False
b.index('Venus') # returns 1 (position index)
And you sort lists alphabetically:
b.sort()
b # returns ['Earth', 'Mercury', 'Venus']
To delete an item from a list:
b.pop(2) # you can use its index
b.remove('Earth') # or you can use its value