python if and else statements error

Question

Please help me with if and else statements in python. I like to set b according to value of a.

a=5
b=0
def fname():
    #less than 5
    if (a < 5): 
        b=100
    #greater than 5 or less than 10
    elif (a >= 5) and (a <= 10):
        b=200
    #greater than 10 or less than 20
    elif (a >10) and (a <= 20):
        b=300
print (b)
fname()

Thanks

Are you calling fname any where ? You don't have any else statements anywhere — jramirez
– jramirez, Commented Oct 27, 2015 at 18:59
umm... do you do realize that a can never be simultaneously under 6 and over 10, right — inspectorG4dget
– inspectorG4dget, Commented Oct 27, 2015 at 19:15
These are the conditions: #if less than 5 b is 100; #greater than or equal 5 and less than 10 b is 200; #greater than or equal 10 and less than 20 b is 300; — Jorge Ben
– Jorge Ben, Commented Oct 27, 2015 at 19:36
printing b before calling fname() is not going to show changes made by fname. — Ethan Furman
– Ethan Furman, Commented Oct 27, 2015 at 19:36

Community · Accepted Answer · 2017-05-23 11:44:50Z

3

The b in fname is not the same b that is in the global/outer scope.

An ugly hack to make that work is to add global b inside fname.

A better way is to pass in the value for a to fname and have fname return the new value for b and assign it:

def fname(a_number):
    #less than 5
    if a_number < 5: 
        return 100
    #greater than 5 or less than 10
    elif 5 <= a_number <= 10:
        return 200
    #greater than 10 or less than 20
    elif 10 < a_number <= 20:
        return 300        

b = fname(a)

See this question for more information about scoping and Python.

edited May 23, 2017 at 11:44

CommunityBot

11 silver badge

answered Oct 27, 2015 at 19:34

Ethan Furman

70.1k21 gold badges174 silver badges251 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

tobias_k Over a year ago

Could also make the conditions more readable using comparison chaining: elif 5 <= a_number <= 10:

VPfB Over a year ago

@EthanFurman: You could also change all elif's to simple if's, because each return ends the function.

Ethan Furman Over a year ago

@VPfB: True, but if just scanning the code the elifs make it clear that only one branch will be executed.

Jorge Ben Over a year ago

how do i test the value of b?

VPfB Over a year ago

@EthanFurman: Just found this: stackoverflow.com/questions/9191388/… We have just different personal preferences.

|

Code Man · Accepted Answer · 2020-06-22 15:07:46Z

0

a = 5
b = 0


def fname():
    # less than 5
    if (a < 5):
        b = 100
        print(b)
    # greater than 5 or less than 10
    elif (a >= 5) and (a <= 10):
        b = 200
        print(b)
    # greater than 10 or less than 20
    elif (a > 10) and (a <= 20):
        b = 300
        print(b)


fname()

if u want to learn about if and else go to - https://youtu.be/no8c4KMYBdU

answered Jun 22, 2020 at 15:07

Code Man

1

Collectives™ on Stack Overflow

python if and else statements error

2 Answers 2

6 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

6 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related