Python: determine if all items of a list are the same item [duplicate]

Question

In some of my code I put a series of objects in a list and I build an additional list out of their attributes, which is a string. I need to determine if all the items in this second list have the exact same value, without knowing beforehand which value it is, and return a bool so that I can do different things in my code depending on the result.

I can't know the names of the properties beforehand, that is why I'm trying to make something as generic as possible.

To make the example clear, an ideal function, called "all_same" would work like this:

>>> property_list = ["one", "one", "one"] >>> all_same(property_list) True >>> property_list = ["one", "one", "two"] >>> all_same(property_list) False 

I was thinking of making a list of unique elements and then check if its length is 1, but I'm not sure if it's the most elegant solution out there.

Answer 1

def all_same(items):     return all(x == items[0] for x in items) 

Example:

>>> def all_same(items): ...     return all(x == items[0] for x in items) ... >>> property_list = ["one", "one", "one"] >>> all_same(property_list) True >>> property_list = ["one", "one", "two"] >>> all_same(property_list) False >>> all_same([]) True 

Answer 2

You could cheat and use set:

def all_same( items ):     return len( set( items ) ) == 1 #== len( items ) 

or you could use:

def all_same( items ):     return all( map(lambda x: x == items[0], items ) ) 

or if you're dealing with an iterable instead of a list:

def all_same( iterable ):     it_copy = tee( iterable, 1 )     return len( set( it_copy) ) == 1