I don't get some syntax for if statements in python:
>> z=[0 if all([2<3,6<7]) else sth] #Correct
>>
>> z=[0 if all([2<3,6<7])] #Wrong
File "<stdin>", line 1
z=[0 if all([2<3,6<7])]
^
SyntaxError: invalid syntax
>>
I don't know this syntax and difference between Correct line and Wrong line?
You're using the A if condition else B syntax in the correct one, which returns an expression to be assigned to your z variable
In the wrong one you're omitting the else clause, so Python can't guess what to put in case your condition all([2<3,6<7]) is not met, which isn't workable so it's not allowed
if you only want to set a value in that case then:
if <condition>:
z = [0]
or if you like one-liners: if <condition>: z = [0]
You cannot skip else while using this syntax. See: http://en.wikipedia.org/wiki/%3F:#Python
List comprehensions doesn't work that way, you thought it like;
def sm():
if somethingelse:
return something
return something1
Probably? In this case we dont have to write else because if if statement works, function is done by return something. But in list comprehensions it's not like that. As you know you don't have to write else in lambda too because lambda is a function too, like the example above.
allcondition was false. What value would you want assigned toz?