W3schools - Python_If / Loop
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If else
Python supports the usual logical conditions from mathematics
a = 33
b = 200
if b > a:
print(“b is greater than a”)
elif a == b: # if the previous condition were not true, then try this condition
print(“a and b are equal”)
else: # Catches anything which isn’t caught by the preceding conditions
print(“a is greater than b”)
# output “b is greater than a”
# short hand
print(“b is greater than a”) if b > a else print(“a and b are equal”) if a == b else print(“a is greater than b”)
pass
if can’t be empty, but if you for some reason have an if with no content, put in the pass to avoid getting an error
Loop
while
Can execute a set of statements as long as a condition is true
It requires relevant var to be ready
i = 1
while i < 6:
if i == 3:
continue # Can stop the current iteration, and continue with the next
if i == 5:
break # Can stop the loop even if the while condition is true
print(i, end=“ ”)
i += 1
# output 1 2 4
else:
print(“blah blah”) # Can run a block of code once when the condition no longer is true
for
Is used for iterating over a sequence
Is less like the for in other programming langs, and works more like an iterator method as found in other OOP langs
With for loop we can execute a set of statements, once for each item in a list, string…
Doesn’t require an indexing var to set beforehand
Can use break, continue, else, pass keyword
friends = [“Patrick”, “Squidward”, “Gary”, “Sandy”]
for x in friends:
print(x, end= “ ”) # output “Patrick” “Squidward” “Gary” “Sandy”
range()
To loop through a set of code a specified number of times, we can use the range()
It returns a sequence of numbers, starting from 0 by default, and increments by 1 by default, and ends at a specified number
for x in range(6):
print(x, end=“ ”) # output 0,1,2,3,4,5
# Can specify detail, parameter (starting value, end value, increment value)
for x in range(2, 10, 2)
print(x, end =“ ”) # output 2,4,6,8