通过修改python中的现有词典来创建新词典

我有一份口述如下

querydict = {u'variantcategoryitem_formset_0-0-variant_category_item_price': [u''], u'variantcategoryitem_formset_0-0-variant_category_item_quantity': [u''], u'variantcategoryitem_formset_0-0-variant_category_item_name': [u'hurray'], }

因此，从上面的字典中，如果没有

price，quantity

字段的值，我应该将值添加为

0（数量），0.0（价格）

如下

new_dict = {}
for key, value in querydict.iteritems():
    # Need to check variant_category_item_qunatity or variant_category_item_price exists in the key, because as u can observe there will be many quantity, price fields in the querydict like variantcategoryitem_formset_0-0-variant_category_item_price, variantcategoryitem_formset_1-1-variant_category_item_price, etc.

    if 'variant_category_item_qunatity' in key:
        # If key exists and if equal to ''(empty string) update the new-dict with this key and value as 0(same in case of price below) 
        if not querydict[key]:
            new_dict[key] = 0
    elif 'variant_category_item_price' in key:
        if not querydict[key]:
            new_dict[key] = 0.0
    # Update the entire new_dict with remaining values
    new_dict[key] = value

---

但它不起作用，我可以在没有数量和价格的情况下看到字典，因此，如果在

querydict

中价格和数量是

'

，那么任何人都可以更正上述逻辑并通过将价格和数量更新为0.0到0来使用querydict值创建新的dict吗？

问题是

querydict

包含一个空字符串的列表，因此

如果不是querydict[key]

始终计算为

False

，因为包含一项的列表不是虚假值

>>> bool([u''])
True

您应将条件更改为：

if querydict[key] == [u'']

• 其次，在循环中，您总是覆盖if-elif条件中设置的值，因此将最后一条语句放在

  else

  块中

• 最后，您在

  “变体\u类别\u项目\u数量”中有一个输入错误
  ：
  

工作版本：

querydict = {u'variantcategoryitem_formset_0-0-variant_category_item_price': [u''], u'variantcategoryitem_formset_0-0-variant_category_item_quantity': [u''], u'variantcategoryitem_formset_0-0-variant_category_item_name': [u'hurray'], }
new_dict = {}
for key, value in querydict.iteritems():

    if 'variant_category_item_quantity' in key: #Typo in quantity spelling in your code
        if querydict[key] == [u'']:
            new_dict[key] = 0

    elif 'variant_category_item_price' in key:
        if querydict[key] == [u'']:
            new_dict[key] = 0.0

    # You need an else condition here, otherwise you'll overwrite the
    # values set in if-elif's         
    else:
         new_dict[key] = value
print new_dict

几个问题：

您在第一个

处有打字错误，如果在
变体(分类)项目(数量)
处有打字错误

则应为

数量

您的

项是未签名字符串的列表，因此必须与正确的类型进行比较

我建议对dict使用

update（）

，这样更容易理解

解决方案如下：

querydict = {u'variantcategoryitem_formset_0-0-variant_category_item_price': [u''], u'variantcategoryitem_formset_0-0-variant_category_item_quantity': [u''], u'variantcategoryitem_formset_0-0-variant_category_item_name': [u'hurray'], }


new_dict = {}

for key, value in querydict.iteritems():
    # Need to check variant_category_item_qunatity or variant_category_item_price exists in the key, because as u can observe there will be many quantity, price fields in the querydict like variantcategoryitem_formset_0-0-variant_category_item_price, variantcategoryitem_formset_1-1-variant_category_item_price, etc.

    if 'variant_category_item_quantity' in key:
        # If key exists and if equal to ''(empty string) update the new-dict with this key and value as 0(same in case of price below)
        if querydict[key] == [u'']:
            new_dict.update({key: 0})
    elif 'variant_category_item_price' in key:
        if querydict[key] == [u'']:
            new_dict.update({key: 0.0})
    # Update the entire new_dict with remaining values
    else:
        new_dict.update({key:value})

print new_dict

{u'variantcategoryitem_formset_0-0-variant_category_item_name': [u'hurray'], u'variantcategoryitem_formset_0-0-variant_category_item_price': 0.0, u'variantcategoryitem_formset_0-0-variant_category_item_quantity': 0}

输出：

querydict = {u'variantcategoryitem_formset_0-0-variant_category_item_price': [u''], u'variantcategoryitem_formset_0-0-variant_category_item_quantity': [u''], u'variantcategoryitem_formset_0-0-variant_category_item_name': [u'hurray'], }


new_dict = {}

for key, value in querydict.iteritems():
    # Need to check variant_category_item_qunatity or variant_category_item_price exists in the key, because as u can observe there will be many quantity, price fields in the querydict like variantcategoryitem_formset_0-0-variant_category_item_price, variantcategoryitem_formset_1-1-variant_category_item_price, etc.

    if 'variant_category_item_quantity' in key:
        # If key exists and if equal to ''(empty string) update the new-dict with this key and value as 0(same in case of price below)
        if querydict[key] == [u'']:
            new_dict.update({key: 0})
    elif 'variant_category_item_price' in key:
        if querydict[key] == [u'']:
            new_dict.update({key: 0.0})
    # Update the entire new_dict with remaining values
    else:
        new_dict.update({key:value})

print new_dict

{u'variantcategoryitem_formset_0-0-variant_category_item_name': [u'hurray'], u'variantcategoryitem_formset_0-0-variant_category_item_price': 0.0, u'variantcategoryitem_formset_0-0-variant_category_item_quantity': 0}

---

我也尝试了上述条件，仍然得到了价格为[''的字典，数量为['']