如果字典的值是一个列表，有没有办法更新字典中键的值？

Question

我有四个特殊字符串列表，例如'™'。我将它们作为键 1 到 4 的值存储在字典中。

我正在尝试遍历每个字典列表中的所有项目，然后将每个值更新为其 utf-8 编码的等效值。这是我目前拥有的：

li1 = ['€','‚','ƒ','„','…','†','ˆ','‰']
li2 = ['Š','‹','Œ','Ž']
li3 = ['‘','’','“','”','•','–','—','˜','™']
li4 = ['š','›','œ','ž','Ÿ']

uni_dic = {
    '1':li1,
    '2':li2,
    '3':li3,
    '4':li4
}

for key in uni_dic:
    for val in uni_dic[key]:
        uni_dic.update({key,val.encode('utf-8')})

这个returns一个'ValueError: dictionary update sequence element #0 has length 1; 2 is required'

Answer 1

取出最后三行写：

for key, values in uni_dic.items():
    uni_dic[key] = [string.encode('utf-8') for string in values]

或一行：

uni_dic = {key: [string.encode('utf-8') for string in uni_dic[key]] for key in uni_dic}

uni_dic}

Answer 2

在这种情况下，您可以创建另一个列表，如下所示：

for key in uni_dic:
    uni_dic[key] = [val.encode('utf-8') for val in uni_dic[key]]

如果你想做in-place:

for key in uni_dic:
    for idx, val in enumerate(uni_dic[key]):
        uni_dic[key][idx] = val.encode('utf-8')

Answer 3

您问题的one-line解决方案是：

uni_dic = {key:[val.encode('utf-8') for val in charList] for key, charList in uni_dic.items()}

要通过对您问题中的代码进行最少的修改来获得相同的结果，您可以这样做：

li1 = ['€','‚','ƒ','„','…','†','ˆ','‰']
li2 = ['Š','‹','Œ','Ž']
li3 = ['‘','’','“','”','•','–','—','˜','™']
li4 = ['š','›','œ','ž','Ÿ']

uni_dic = {
    '1':li1,
    '2':li2,
    '3':li3,
    '4':li4
}

for key in uni_dic:
    charList = uni_dic[key]
    for i, val in enumerate(charList):
        charList[i] = val.encode('utf-8')
[print(charList) for charList in uni_dic.values()]

输出：

[b'\xe2\x82\xac', b'\xe2\x80\x9a', b'\xc6\x92', b'\xe2\x80\x9e', b'\xe2\x80\xa6', b'\xe2\x80\xa0', b'\xcb\x86', b'\xe2\x80\xb0']
[b'\xc5\xa0', b'\xe2\x80\xb9', b'\xc5\x92', b'\xc5\xbd']
[b'\xe2\x80\x98', b'\xe2\x80\x99', b'\xe2\x80\x9c', b'\xe2\x80\x9d', b'\xe2\x80\xa2', b'\xe2\x80\x93', b'\xe2\x80\x94', b'\xcb\x9c', b'\xe2\x84\xa2']
[b'\xc5\xa1', b'\xe2\x80\xba', b'\xc5\x93', b'\xc5\xbe', b'\xc5\xb8']

Answer 4

语法错误是您将更新指令指定为 {key,val.encode('utf-8')}（实际上是 set）而不是 {key: val.encode('utf-8')}。但是，无论如何使用 update 来更新单个键有点愚蠢，并且它们循环遍历列表的方式，您只需依次用每个元素重复覆盖列表（最终以最后一项）。

相反，从编码值构建一个新列表，并将 整个列表 分配给 uni_dic[key]:

for key in uni_dic:
    encoded_vals = []
    for val in uni_dic[key]:
        encoded_vals.append(val.encode('utf-8'))
    uni_dic[key] = encoded_vals

使用列表推导来构建 encoded_vals 让您更加简洁：

for key in uni_dic:
    uni_dic[key] = [val.encode('utf-8') for val in uni_dic[key]]

使用 dict.items() 的字典理解使它更简单：

uni_dic = {k: [val.encode('utf-8') for val in v] for k, v in uni_dic.items()}

如果字典的值是一个列表，有没有办法更新字典中键的值？

Is there a way to update the value of a key in a dictionary, if the value of the dictionary is a list?

python

dictionary

nested