In this section you learned that:

• For loops are useful for executing a command over a large number of items.

• You can create a for loop like so:

for letter in 'abc':
    print(letter.upper())

Output:

A
B
C

• The name after for (e.g. letter) is just a variable name

  
  

• You can loop over dictionary keys:

phone_numbers = {"John Smith":"+37682929928","Marry Simpons":"+423998200919"}
for value in phone_numbers.keys():
    print(value)

Output:

John Smith
Marry Simpsons

• You can loop over dictionary values:

phone_numbers = {"John Smith":"+37682929928","Marry Simpons":"+423998200919"}
for value in phone_numbers.values():
    print(value)

Output:

+37682929928
+423998200919

• You can loop over dictionary items:

  phone_numbers = {"John Smith":"+37682929928","Marry Simpons":"+423998200919"}
  for key, value in phone_numbers.items():
      print(key, value)

  Output: 

  ('John Smith', '+37682929928')

  ('Marry Simpons', '+423998200919')

• While loops will run as long as a condition is true:

  while datetime.datetime.now() < datetime.datetime(2090, 8, 20, 19, 30, 20):
      print("It's not yet 19:30:20 of 2090.8.20")

  The loop above will print out the string inside print() over and over again until the 20th of August, 2090.