Question

我有一个dict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'], }

所以从上面的字典中，如果它没有price, quantity字段的值，我应该将这些值添加为0(quantity), 0.0(price)

如下所示

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

但是它不起作用，我能够看到没有数量和价格值的字典，所以任何人都可以通过将价格和数量更新为0.0到0来纠正上述逻辑并使用querydict值创建新的dict，如果它们是''中的querydict？

Answer 1

问题是querydict包含一个包含空字符串的列表，因此if not querydict[key]始终评估为False，因为包含一个项目的列表不是虚假值。

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

您应该将条件更改为：

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

其次在你的循环中你总是覆盖if-elif条件中设置的值，所以把最后一个语句放在else块中。
最后您在'variant_category_item_qunatity'中输了一个拼写错误：

工作版：

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

Answer 2

几个问题：

您在第if variant_category_item_qunatity处有拼写错误quantity
您的item是无符号字符串列表，因此您必须与正确的类型进行比较。
我建议将update()与dict一起使用，理解起来更清楚......

以下是解决方案：

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

<强>输出：

{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}

通过修改python中的现有字典来创建新字典

2 个答案: