Question

我有一个字典，每个字母都有两个值。我需要更新第二个值作为传递重复键。显然，我尝试的并不是很有效。

if value1 not in dict.keys():
    dict.update({key:(value1,value2)})
else:
    dict.update({key:value1,+1)})

这只返回了一个值为2的1s而不是递增1

Answer 1

表达式+1不会增加任何内容，它只是数字1

同时避免使用dict作为名称，因为它是Python built-in

尝试更像这样构建代码：

my_dict = {} # some dict
my_key = # something

if my_key not in my_dict:
    new_value = # some new value here
    my_dict[my_key] = new_value
else:
    # First calculate what should be the new value

    # Here I'm doing a trivial new_value = old_value + 1, no tuples
    new_value = my_dict[my_key] + 1
    my_dict[my_key] = new_value

    # For tuples you can e.g. increment the second element only
    # Of course assuming you have at least 2 elements,
    # or old_value[0] and old_value[1] will fail
    old_value = my_dict[my_key] # this is a tuple
    new_value = old_value[0], old_value[1] + 1
    my_dict[my_key] = new_value

_{可能有更短或更聪明的方法，例如使用运算符+=，但为了清楚起见，编写了此代码段}

Python：使用元组值更新字典键

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