Question

a = 20
if a >= 22:
   print("if")
elif a >= 21:
    print("elif")
else:
    print("else")

Again, nothing remarkable here, just need to learn the syntax. Here, we should also mention spacing. Python is picky about indentation - you must start a newline after each conditional statemen (it is the same for the iterators above) and indent the same number of spaces for every statement within the scope of that condition.

a = 23
if a >= 22:
   print("if")
    print("greater than or equal 22")
elif a >= 21:
    print("elif")
else:
    print("else")

a = 23
if a >= 22:
   print("if")
   print("greater than or equal 22")
elif a >= 21:
    print("elif")
else:
    print("else")

Four spaces are customary, but you can use whatever you like. Consistency is necessary.

Python has another type of conditional expression that is very useful. Suppose your program is processing user input or data from a file. You don’t always know for sure what you are getting in that case, and this can lead to problems. The ‘try/except’ conditional can solve them!

a = "1"

try:
  b = a + 2
except:
  print(a, " is not a number")

Here, we have tried to add a number and a string. That generates an exception - but we have trapped the exception and informed the user of the problem. This is much preferable to the programming crashing with some cryptic error like:

a = "1"
b = a + 2