这个Python循环可以更简洁地表达吗？

Question

我遇到了一些Python v2.7代码，我将其重构为：

for ssid in (ssid for ssid in overlaps
             if ssid != subseq_id and ssid not in merged):

但我觉得应该有一种不用两个for语句就能表达的方法？你知道吗

Answer 1

根据您的数据（顺序不重要，…），您可以使用集合：

excluded = set(merged)
excluded.add(subseq_id)
ssids = set(overlaps) - excluded
for ssid in ssids:
    ...

Answer 2

您可以使用filter()：

for ssid in filter(lambda s: s != subseq_id and s not in merged, overlaps):
    # ...

或者你可以在循环中测试：

for ssid in overlaps:
    if ssid == subseq_id or ssid in merged:
      continue
    # ...