python - 为什么这个 elif 语句给我一个错误？

Question

我不明白为什么我的elif陈述中有错误。

我正在将 eclipse 插件pydev与最新版本的 python 一起使用。

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：

“在第 42 行第 54 列遇到“<”。期待以下之一：“（”...“{”...“[”...“。”...“+”...“-” ...“〜”...“不”...“异步”...“等待”...“假”...“真”...“无”... ... .. . ... ... ... ... ... "\'" ... "\"" ... "\'\'\'" ... "\"\"\"" 。 .. "\'" ... "\"" ... "\'\'\'" ... "\"\"\"" ... "\'" ... "\"" 。 .. "\'\'\'" ... "\"\"\""... "\'" ... "\"" ... "\'\'\'" ... "\"\"\"" ...

Answer 1

你的意思？

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

是and一个布尔运算符。每边都需要两个操作数。但< 21不是一种表达方式。

在 Python 中，您可以更简洁地将其编写为：

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

Answer 2

用这个：

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

Answer 3

您应该and从代码中删除：

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

它应该如下所示：

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

Answer 4

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

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

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

或者

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

根据您的要求

Answer 5

好吧，如果我能清楚地了解您要做什么，我将能够帮助编写代码。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。变量需要在and运算符的两侧进行测试。