Python混合了两个列表，我不知道为什么

Question

以下是代码：

import requests
import bs4

response = requests.get('http://discoverygc.com/forums/serverinterface.php?action=players_online') #Loads page
soup = bs4.BeautifulSoup(response.text)
table = soup.find("div", {"id": "forum"})
rowsNo = (str(table).count('<tr>') - 2) #Number of players online. Minus 2 to remove leading title and column description rows
players = systems = [] #Define lists
for i in range(3, (rowsNo + 3)):
    rows = table.findAll('tr')[i]
    cols = rows.findAll('td')
    player = cols[0].get_text()
    system = cols[1].get_text()
    players.append(player)
    systems.append(system)

print(players)
print(systems)

如果删除players.append(player)或systems.append(system)，代码工作正常，并输出正确的列表：

['-Vasqez-', '[-=XTF=-]Neon.Bunny-[R]', "[SV]-Valley'", '<-JohnyWalker->', '~VP)Bad.Tibira', 'Alkanius', 'Apex91', 'Araroba', 'Baldor', 'Benediction', 'Black_Bird', 'Boost', 'Caelius.Moya[X]', 'Core|APM-Maverick', 'Daftwagen', 'Dee.Leers', 'Emiko:Hayashi', 'Gamma-6', 'Gauri', 'Gigi.7', 'GMG|GTS-Komahashi-Maru', 'Grawmod', 'GrazySlon', 'Hunor', 'Jakob-Schleiter', 'Joyita', 'Judge_BigJo', 'JulyJalwa', 'Kruger|KMS-Lankow', 'Luxor', 'monitor91', 'Morgulis', 'Nuggets', 'OSI-Mendes', 'Ronny.Rochester', 'Samura|-Arata', 'Samura|-Ichikawa', 'Shpritzen', 'Stardrifter', 'The_Altair', 'The.Liner.of.Dreams', 'Tony.Sosa', 'Wilde.RNC-Nestor']

或者：

['Omega-11', 'Omega-49', 'Pennsylvania', 'Magellan', 'Omicron Gamma', 'Kyushu', 'Pennsylvania', 'Kyushu', 'Omega-5', 'Manchester', 'Cassini', 'Newcastle', 'Connecticut', 'Omega-47', 'Stuttgart', 'Stuttgart', 'Munich', 'New York', 'Hudson', 'Sigma-13', 'Languedoc', 'Colorado', 'Virginia', 'Stuttgart', 'New London', 'Magellan', 'New York', 'New Tokyo', 'Manchester', 'New York', 'Pennsylvania', 'Omega-3', 'Omega-49', 'New Berlin', 'California', 'Nagano', 'New Berlin', 'Okinawa', 'Magellan', 'Texas', 'Ontario', 'New Berlin', 'Stuttgart']

但是，如果我将这两行放在一起，那么这两个列表都混合在一起：

['-Vasqez-', 'Omega-11', "[SV]-Valley'", 'Omega-49', '<-JohnyWalker->', 'Pennsylvania', '=Z=Exositas', 'Magellan', '~VP)Death.Incarnator', 'Omicron Gamma', 'Alkanius', 'Shikoku', 'Apex91', 'Pennsylvania', 'Baldor', 'Kyushu', 'Benediction', 'Omega-5', 'Black_Bird', 'Manchester', 'Boost', 'Cassini', 'Caelius.Moya[X]', 'Connecticut', 'Core|APM-Maverick', 'Omega-47', 'Daftwagen', 'Stuttgart', 'Darf.Acour', 'Texas', 'Dee.Leers', 'New Berlin', 'Emiko:Hayashi', 'Munich', 'Gamma-6', 'New York', 'Gauri', 'Hudson', 'Gigi.7', 'Orkney', 'GMG|GTS-Komahashi-Maru', 'Colorado', 'Grawmod', 'Virginia', 'GrazySlon', 'Stuttgart', 'Hunor', 'Manchester', 'Jakob-Schleiter', 'New Berlin', 'Joyita', 'Magellan', 'Judge_BigJo', 'New York', 'Kruger|KMS-Lankow', 'New Tokyo', 'Luxor', 'Manchester', 'monitor91', 'New York', 'Morgulis', 'Pennsylvania', 'Nuggets', 'Omega-3', 'OSI-Mendes', 'Omega-49', 'Ronny.Rochester', 'California', 'Samura|-Arata', 'Nagano', 'Samura|-Ichikawa', 'New Berlin', 'Stardrifter', 'Okinawa', 'The_Altair', 'Magellan', 'Tony.Sosa', 'Ontario', 'Wilde.RNC-Nestor', 'Omega-7']

为什么会这样呢？我看不出有什么理由要这样做。

Answer 1

不要这样做，他们会引用相同的列表：

players = systems = [] #Define lists

但是把它们分开：

players = []
systems = [] #Define lists

然后你将有两个单独的列表。

您的样式用于创建列表的名称别名(在某些情况下可能有用)，而不是创建两个不同的列表。

Answer 2

让players = systems = []把它改为单独的作业。

players = []
systems = []

Answer 3

如果你想把它写成一行：

players, systems = [], []