Question: I found, that there is related question, about how to find if at least one item exists in a list:  

[How to check if one of the following items is in a list?](https://stackoverflow.com/questions/740287/python-check-if-one-of-the-following-items-is-in-a-list)

But what is the best and pythonic way to find whether all items exists in a list?

Searching through the docs I found this solution:

```
>>> l = ['a', 'b', 'c']
>>> set(['a', 'b']) <= set(l)
True
>>> set(['a', 'x']) <= set(l)
False

```

Other solution would be this:

```
>>> l = ['a', 'b', 'c']
>>> all(x in l for x in ['a', 'b'])
True
>>> all(x in l for x in ['a', 'x'])
False

```

But here you must do more typing.

Is there any other solutions?

Answer: 
Operators like `<=` in Python are generally not overriden to mean something significantly different than "less than or equal to". It's unusual for the standard library does this--it smells like legacy API to me.

Use the equivalent and more clearly-named method, `set.issubset`. Note that you don't need to convert the argument to a set; it'll do that for you if needed.

```
set(['a', 'b']).issubset(['a', 'b', 'c'])

```
I like these two because they seem the most logical, the latter being shorter and probably fastest (shown here using `set` literal syntax which has been [backported](https://docs.python.org/dev/whatsnew/2.7.html#other-language-changes) to Python 2.7):

```
all(x in {'a', 'b', 'c'} for x in ['a', 'b'])
#   or
{'a', 'b'}.issubset({'a', 'b', 'c'})

```