red_always_mafia - 3 months ago 6x
Python Question

# Invalid Syntax Error with If statement

So when i try to run this, i get Invalid syntax on the second if statement, highlighting the colon. I don't understand why this is occurring, as far as i can see, they're basically the same. So why does the second if statement return invalid syntax but the first doesnt?

``````for event in pygame.event.get():
if event.type == MOUSEBUTTONDOWN :
if ROption1Exists == True:
rx, ry = event.pos
if rx >= (100*((X+3)+1)) and rx <= (100*((X+3)+2)) and ry >= (100*(Y+1)) and ry <= (100*(Y+2)):
print('babies')
VarReset()
Pos = ((X+3), Y)
if ROption2Exists == True:
rx, ry = event.pos
if rx >= (100*((X-3)+1)) and rx <= (100*((X-3)+2)) and ry >= (100*((Y+1)) and ry <= (100*(Y+2)):
print('babies')
VarReset()
Pos = ((X-3), Y)
``````

You have a parenthesis balance problem:

``````if rx >= (100*((X-3)+1)) and rx <= (100*((X-3)+2)) and ry >= (100*((Y+1)) and ry <= (100*(Y+2)):
#        1    23   2  10           1    23   2  10           1    23   21           2    3   21
#                      ^ all closed              ^ all closed           ^ uhoh
``````

You have one opening parenthesis too many, or one closing parenthesis too few.

You can cut back a little on all those parenthesis, the following suffices:

``````if rx >= 100*(X-2) and rx <= 100*(X-1) and ry >= 100*(Y+1) and ry <= 100*(Y+2):
``````

You can chain the comparison operators:

``````if 100*(X-1) >= rx >= 100*(X-2) and 100*(Y+2) >= ry >= 100*(Y+1):
``````

where `100*(X-1) >= rx >= 100*(X-2)` is logically the same as `100*(X-1) >= rx and rx >= 100*(X-2)` but `rx` is evaluated only once; all you had to do was invert the `<=` operators by swapping the operands.

Note that testing for equality to `True` is rarely required; just drop the `== True` from your `if` statements:

``````if ROption1Exists:
``````
Source (Stackoverflow)