Issue #18652: Add an itertools recipe for first_true()

1 files changed, 13 insertions, 0 deletions

diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst
index 5d3e50a..f489535 100644
--- a/Doc/library/itertools.rst
+++ b/Doc/library/itertools.rst
@@ -784,6 +784,19 @@ which incur interpreter overhead.
        except exception:
            pass
 
+   def first_true(iterable, default=False, pred=None):
+       """Returns the first true value in the iterable.
+
+       If no true value is found, returns *default*
+
+       If *pred* is not None, returns the first item
+       for which pred(item) is true.
+
+       """
+       # first_true([a,b,c], x) --> a or b or c or x
+       # first_true([a,b], x, f) --> a if f(a) else b if f(b) else x
+       return next(filter(pred, iterable), default)
+
    def random_product(*args, repeat=1):
        "Random selection from itertools.product(*args, **kwds)"
        pools = [tuple(pool) for pool in args] * repeat