find_first
获得列表中第一个元素
Source
python
def find_first(self) -> Optional[T]:
try:
return next(self._stream)
except StopIteration:
return None
Usage
获得列表中第一个元素
python
a = [1, 2, 3]
b = Stream(a).find_first()
assert b == 1
a = []
b = Stream(a).find_first()
assert b is None
等价的 java 代码
java
List<Integer> a = Arrays.asList(1, 2, 3);
Optional<Integer> b = a.stream()
.findFirst();
a = Arrays.asList();
b = a.stream()
.findFirst();