python 3中的elif错误

Question

I started python a couple of days back..now learning to use 'if' and 'elif'...created a basic program....when I use elif, it shows me

syntax error:invalid syntax

print('welcome to my calculator')
num1 = int(input('enter the first number:'))
num2 = int(input('enter the second number:'))
print('select options')
functions = ['Add','Sub','Mul','Div']
print (functions)
options = input("enter the desired option:")
if options == 'Add':
    print(num1+num2)
print('num1+num2=', num1+num2) 
elif options == 'Sub':
    print(num1-num2)
print('num1-num2=', (num1-num2))

when I ran this, I got the following error

elif options == 'Sub':
       ^
SyntaxError: invalid syntax

Process finished with exit code 1

Can anyone help me solve this error?

Answer 1

For python you need to have everything inside of your if, elif and else at the same indention. Change it to

if options == 'Add':
    print(num1+num2)
    print('num1+num2', num1+num2)
elif options == 'Sub':

Answer 2

print('welcome to my calculator')
num1 = int(input('enter the first number:'))
num2 = int(input('enter the second number:'))
print('select options')
functions = ['Add','Sub','Mul','Div']
print (functions)
options = input("enter the desired option:")
if options == 'Add':
    print(num1+num2)
    print('num1+num2=', num1+num2) 
elif options == 'Sub':
    print(num1-num2)
    print('num1-num2=', (num1-num2))
else:                    # you need this line as well
    print("continue... remaining logic")

Answer 3

The problem in your script is in the indetention. Basically, in order to fix the problem, you should change your code in this way:

options = input("enter the desired option:")
if options == 'Add':
    print(num1+num2)
    print('num1+num2=', num1+num2) 
elif options == 'Sub':
    print(num1-num2)
    print('num1-num2=', (num1-num2))

In your code, the line print('num1+num2=', num1+num2) ended the if statement, and so elif doesn't have any meaning

Answer 4

Put the "prints" inside the "if" statements and that's it. It worked for me:

welcome to my calculator
enter the first number:3
enter the second number:2
select options
['Add', 'Sub', 'Mul', 'Div']
enter the desired option:Sub
1
num1-num2= 1

Tried also the 'Add' option.