Question

我有一个包含整数值的Python列表。例如，以下列表：

p = [10,44,55,33]

现在，我想测试列表中的至少一个值是否落入给定间隔。例如，如果我们有间隔[15,30]，则它是错误的，因为在此间隔中，p中没有值。如果我们有间隔[50,60]，则为真，因为55在此间隔中。

我不仅像上面的示例那样在列表中有4个值，而且还有数十个tousand，所以我搜索了最有效的方法。最好的方法是什么？

Answer 1

尝试将any与生成器表达式一起使用：

>> any(50 < e < 60 for e in p)
True

在第一个检查结果为真之前，它只会生成尽可能多的检查结果。

Answer 2

除非对p进行排序，否则最好的办法是扫描p的每个元素并检查它是否在间隔中。

您可以这样做：

any( interval_low <= i <= interval_high for i in p )

Answer 3

p = [10,44,55,33]
i = [10,50]

sol = list(filter(lambda x: x in range(i[0],i[1]+1),p))
# output [10, 44, 33]

Answer 4

使用列表理解

from twisted.internet import threads, reactor
from twisted.internet.defer import inlineCallbacks, returnValue
from time import sleep


class SomeClass(object):
    def __init__(self):
        self.working = False

    def set_working(self, is_working):
        self.working = is_working
        print 'Flag set to {}'.format(is_working)

    @inlineCallbacks
    def do_worker_thread(self):

        # I want to make this call on the main thread
        self.set_working(True)

        # I want to do all this garbage on a separate thread and keep trucking on the main thread
        # This mimics some calls in the real code. There is a call to deferToThread and a try
        # except block there.
        def thread_proc():
            try:
                for i in xrange(0, 10):
                    print 'Step {} starting'.format(i)
                    self.execute_step(i)
            except Exception:
                print 'An exception happened'

        yield threads.deferToThread(thread_proc)

        # When the worker thread is done, I want to call back 'on_thread_work_done'
        self.on_thread_work_done()

        returnValue(17)

    def execute_step(self, num):
        sleep(1)
        print 'Worker thread: {}'.format(num)

    def on_thread_work_done(self):
        """I want to be called back when the worker thread is done"""
        self.set_working(False)

    def do_main_thread(self):
        for i in [chr(x) for x in range(ord('a'), ord('z')+1)]:
            print 'Main thread: {}'.format(i)
            sleep(1)

    def thread_done(self, result):
        print 'Thread done: {}'.format(result)

if __name__ == "__main__":
    someClass = SomeClass()
    # Schedule the threaded work
    result = someClass.do_worker_thread().addCallback(someClass.thread_done)
    # Schedule the main thread work
    reactor.callFromThread(someClass.do_main_thread)
    reactor.run()

检查值是否在间隔内

4 个答案: