Need help wioth elif

[michael_lwt]

a = int(input("What is your age : "))
b = int(input("How long have you beed in this address ? "))
c = float(input("What is your annual income ? "))
print (a)
print (b, " years")
print ("$ %8.2f" %c)

#age 

if ( a < 20 ):
    p = -10 
elif ( a > 21 & a < 30 ):
    p = 0 
elif ( a > 31 & a <= 50 ):
       print("Hi")
       p = 20
elif ( a > 50 ):
         p = 25 

print(p) 


if ( b < 1 ):
     p=p-5
elif ( b > 1 & b < 3 ):
     p=p+5
elif ( b > 4 & b < 8 ):
     p=p+12
elif ( b > 8 ):
     p=p+20

print(p)

Output

Output:
What is your age : 50
How long have you beed in this address ? 2
What is your annual income ? 200
50
2  years
$   200.00
0
5
 

Can you please help as the 3rd elif does not get execued

buran write Dec-19-2021, 04:43 AM:
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[deanhystad]

In Python the logical and is "and". "&" is a bitwise arithmetic and, just like it is in C. But this is Python so dump the unnecessary parenthesis. And while you are at it dump the 1 letter variable names. Use meaningful variable names.

if age < 20:
    p = -10
elif age >= 20 and age < 30:
    p = 0

This works, but it is still wrong. You aren't thinking about how the if and the elif work together. You are writing code like this:

if age < 20:
    p = -10  # I would rename p if I knew what it represented
if 20 <= age < 30:   # This is more readable than age >= 20 and age < 30, but it is still wrong.
    p = 0
if 30 <= age <= 50:
    p = 20
if age > 50:
    p = 25

Each of your conditional tests stands on it's own age < 20, 20 < age < 30 and so on. When you add an elif you are not taking advantage of what you already know.

if age < 20:
    p = -10
elif # How SHOULD we test for 20 <= age < 30?

If age is < 20 the program sets p to -10 and the jumps out of the if/elif. If the program reaches the elif you know that age is not < 20, so you don't need to test for that condition again.

if age < 20:
    p = -10
elif age < 30:  # We know age >= 20 if we get here.
    p = 0

The same goes for the next elif. If age < 30 you would not be reaching the next elif, so you don't have to test for < 30 again.

if age < 20:
    p = -10
elif age < 30:
    p = 0
elif age <= 50:
    p = 20
else:   # We know age > 50 if we get here.  No need to test
    p = 25