Python if x is not None statement-CodePudding

This is my code:

level = '(Something '
level = re.sub(r'[()]', '', str(level).lower()) if level is not None else None

How can I code this properly?

If I dont include the "else None" part it raises an error. I want to apply second line only if level is not None, otherwise ignore it. Is there a way of ignoring the operation in case level is None, using only 1 Python line?

CodePudding user response：

It's not possible to exclude the 'else' in a one line conditional however one workaround would be the following:

level = '(Something '
level = re.sub(r'[()]', '', str(level).lower()) if level is not None else level

CodePudding user response：

Why not just

level = '(Something '
if level is not None:
    level  = re.sub(r'[()]', '', str(level).lower())

CodePudding user response：

If I dont include the "else None" part it raises an error.

Indeed, you have used ternary operator which is ternary.

Is there a way of ignoring the operation in case level is None, using only 1 Python line?

You can use normal if without return after :, consider following simple example

x = 0
if x>0: x=10
print(x)

which output 0 as is, 10 if you change x to 1. Important: before usage consult your organization's standing coding style requirements to see if such code is compliant with them.

CodePudding user response：

What about turning it from two lines into one line, like this:

level = re.sub(r'[()]', '', str(level).lower()) if level is not None else '(Something '

I don't know how can level be None when you assign '(Something ' to it in the first line (as someone already pointed out in the comments). But if you merge those two lines into one, then there is a chance that level could be None. Hence, the logic is a little bit different than what you wrote.

CodePudding user response：

I don't know what re is, but your else statement is redundant. Try the following:

level = '(Something ' 
level  = re.sub(r"[()]", "", str(level).lower()) if not level is None

CodePudding user response：

Try this ? This is much common

level = '(Something ' # Create variable
if level is not None: # If statement
    level  = re.sub(r'[()]', '', str(level).lower()) # Execute the command needed