Python Else/Elif Syntax Error: Troubleshooting Tips and Common Mistakes

In summary, the conversation discusses the frustration of using Python version 2.7.1, specifically with regards to the else statement. The expected output is 'Even', but the system continues to give syntax errors. The correct syntax for the else statement is to indent it at the same level as the if statement and have it on a separate line. The conversation ends with a request for help and appreciation for any assistance.
  • #1
clope023
992
131
Hello, the title says it all; I am trying to teach myself Python using version 2.7.1 aka matplotlib or PYLAB via the MIT opencourseware as well as the tutorial from the site I downloaded it from; I am having a very frustrating time using it as system continues to return any variant of else statements as syntax errors.

An attempted example program is as follows:

x = 2

if (x/2)*2 == x:
... print 'Even'
... else: print 'Odd'
...
...
'Even'

This would be my expected output but, python continues to give me a syntax error whenever I use the else statement. I've tried it without the colons, I've tried added the else's command on another line, I've tried using the elif function and nothing works the editor contiues to give syntax errors.

I know I'm using the correct code as I am pulling several examples from the tutorial and they've all been correct except this one. Does python 2.7.1 not recognize else statements? Does anyone know if the syntax has changed? Does anyone know the correct syntax? Any and all help is greatly appreciated.
 
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  • #2
The else statement needs to be indented at the same level as the if, the else suite needs to be on a separate line (or lines), and this suite needs to be indented at the same at the same level as the if suite. e.g.

Code:
...
if (x/2)*2 == x:
   print 'Even'
else:
   print 'Odd'
...
 
  • #3
D H said:
The else statement needs to be indented at the same level as the if, the else suite needs to be on a separate line (or lines), and this suite needs to be indented at the same at the same level as the if suite. e.g.

Code:
...
if (x/2)*2 == x:
   print 'Even'
else:
   print 'Odd'
...

Thanks very much!
 

1. What is the main purpose of the "else" keyword in Python?

The "else" keyword in Python is used to specify a block of code that should be executed when the condition in an "if" statement is not met. It provides an alternate path of execution when the "if" condition is false.

2. How is the "elif" keyword different from the "else" keyword?

The "elif" keyword is used to specify a new condition to be checked if the previous "if" and "elif" conditions are not met. It can be used multiple times in a single "if" statement to provide multiple alternate paths of execution. The "else" keyword, on the other hand, is only executed when all previous conditions in the "if" statement are false.

3. What is the correct syntax for using "else" and "elif" in a single "if" statement?

The correct syntax is:
if condition1:
    code to be executed if condition1 is true
elif condition2:
    code to be executed if condition2 is true
else:
    code to be executed if all previous conditions are false
Note that the "else" statement is optional, but there can only be one "else" statement per "if" statement.

4. What are some common causes of a syntax error in "else/elif" statements?

Some common causes of syntax errors in "else/elif" statements include missing or incorrect indentation, missing or incorrect colon after the "if" or "elif" condition, and using "else" without a corresponding "if" statement. It is also important to make sure that the conditions in the "if" and "elif" statements are properly written and evaluated to a boolean value.

5. How can I fix a "Python else/elif syntax error"?

The best way to fix a "Python else/elif syntax error" is to carefully check the syntax of your code and ensure that all indentation, colons, and keywords are used correctly. It may also be helpful to use an integrated development environment (IDE) or a syntax checker to identify any errors. If you are still having trouble, you can consult online resources or seek help from a more experienced programmer.

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