Pythonic way of checking if a condition holds for any element of a list
PythonListPython Problem Overview
I have a list in Python, and I want to check if any elements are negative. Specman has the has() method for lists which does:
x: list of uint;
if (x.has(it < 0)) {
// do something
};
Where it is a Specman keyword mapped to each element of the list in turn.
I find this rather elegant. I looked through the [Python documentation][1] and couldn't find anything similar. The best I could come up with was:
if (True in [t < 0 for t in x]):
# do something
I find this rather inelegant. Is there a better way to do this in Python?
[1]: http://docs.python.org/library/stdtypes.html#typesseq-mutable "Python Built-in Types"
Python Solutions
Solution 1 - Python
if any(t < 0 for t in x):
# do something
Also, if you're going to use "True in ...", make it a generator expression so it doesn't take O(n) memory:
if True in (t < 0 for t in x):
Solution 2 - Python
Use any().
if any(t < 0 for t in x):
# do something
Solution 3 - Python
Python has a built in http://docs.python.org/library/functions.html#any">any()</a> function for exactly this purpose.