为什么这个 elif 语句会给我一个错误？

Question

我不明白为什么我的 elif 语句中出现错误。

我正在使用带有最新版本 python 的 eclipse 插件 pydev。

例如，

if  sum(player_cards) = 14 and sum(computer_cards) = 10

这应该输出为 True

elif sum(player_cards) > sum(computer_cards) and < 21 :

相反，它给了我这个：

"Encountered "<" at line 42, column 54. Was expecting one of: "(" ... "{" ... "[" ... "." ... "+" ... "-" ... "~" ... "not" ... "async" ... "await" ... "False" ... "True" ... "None" ... ... ... ... ... ... ... ... "\'" ... "\"" ... "\'\'\'" ... "\"\"\"" ... "\'" ... "\"" ... "\'\'\'" ... "\"\"\"" ... "\'" ... "\"" ... "\'\'\'" ... "\"\"\"" ... "\'" ... "\"" ... "\'\'\'" ... "\"\"\"" ...

Answer 1

你的意思是？

elif sum(player_cards) > sum(computer_cards) and sum(player_cards) < 21:

and 是布尔运算符。它的每一侧都需要两个操作数。但是 < 21 不是表达式。

在Python中，可以更简洁地写成：

elif 21 > sum(player_cards) > sum(computer_cards):

Answer 2

使用这个：

elif (sum(player_cards) > sum(computer_cards)) and (sum(player_cards)< 21):

Answer 3

您应该从代码中删除 and：

elif sum(player_cards) > sum(computer_cards) and < 21:

它应该是这样的：

elif sum(player_cards) > sum(computer_cards) < 21

Answer 4

错误是语法无效，请参阅 20 > 10 和 < 21，您将 21 与什么进行比较？你也必须指定它。

elif sum(player_cards) > sum(computer_cards) 并且 < 21 应该是

elif sum(player_cards) > sum(computer_cards) and sum(computer_cards) < 21

或

 elif sum(player_cards) > sum(computer_cards) and sum(player_cards) < 21

取决于您的要求

Answer 5

好吧，如果我能清楚地了解您正在尝试做什么，我将能够帮助您编写代码。但是，这里的语法似乎不正确：

sum(player_cards) > sum(computer_cards) and < 21

相反，我会这样做：

if (condition):
    <statements here>
elif ((sum(player_cards) > sum(computer_cards)) and (sum(player_cards)< 21)):
    <statements here>
else:
    return

注意括号的使用。需要在和运算符的任一侧测试变量。

为什么这个 elif 语句会给我一个错误？

why does this elif statement give me an error?

python

and-operator