如何在Python中处理更复杂的计时需求，比如分段计时？

在Python中处理复杂的计时需求，比如分段计时，你可以使用类和函数来构建一个更健壮的计时器系统。例如，可以设计一个`SegmentedTimer`类，它包含开始、停止、暂停和继续等方法。下面是一个简单的示例：

import time
from collections import defaultdict

class SegmentedTimer:
    def __init__(self):
        self.segments = defaultdict(lambda: {"start": None, "end": None})

    def start_segment(self, label=None):
        if label:
            self.segments[label] = {"start": time.time()}
        else:
            label = "unnamed_segment"
            self.segments[label]["start"] = time.time()

    def stop_segment(self, label=None):
        if label and label in self.segments:
            self.segments[label]["end"] = time.time()
        elif "unnamed_segment" in self.segments:
            self.segments["unnamed_segment"]["end"] = time.time()
        else:
            print("No active segment to stop.")

    def pause_segment(self, label):
        if label in self.segments:
            self.segments[label]["paused"] = time.time()

    def resume_segment(self, label):
        if label in self.segments and "paused" in self.segments[label]:
            self.segments[label]["end"] = time.time()
            del self.segments[label]["paused"]

    def get_elapsed_time(self, label):
        if label in self.segments:
            return self.segments[label]["end"] - self.segments[label]["start"]
        else:
            return None

# 使用示例
timer = SegmentedTimer()
timer.start_segment('segment1')  # 开始计时
time.sleep(2)  # 模拟活动
timer.pause_segment('segment1')
time.sleep(1)
timer.resume_segment('segment1')
timer.stop_segment('segment1')  # 停止并获取时间