python数组避坑操作（比如删除数组中的所有0）

一、演示坑

tracks = [0, 0, 0, 1, 1, 1]
for track in tracks:
    if track == 0:
        tracks.remove(track)
print(tracks) # [0, 1, 1, 1]

发现：有一个0没有被删去，why???

二、这次遍历时，带上索引打印

tracks = [0, 0, 0, 1, 1, 1]
for index, track in enumerate(tracks):
    if track == 0:
        tracks.remove(track)
    print(index, track)
'''
会依次打印：
    0 0
    1 0
    2 1
    3 1
'''
print(tracks)  # [0, 1, 1, 1]

发现：数组在remove操作后，遍历时索引依次递增，但是数组长度在减小，取值时在更新后的数组按索引取，因此会跳过一些元素

三、如何实现数组去0操作？

• 方式一

  tracks = [0, 0, 0, 1, 1, 1]
  for i in range(tracks.count(0)):
      tracks.remove(0)
  print(tracks)  # [1, 1, 1]

• 方式二

  tracks = [0, 0, 0, 1, 1, 1]
  newTracks = []
  for track in tracks:
      if track != 0:
          newTracks.append(track)
  print(newTracks)  # [1, 1, 1]

  借助了新数组