django输出空csv

Question

我正在使用django，正在尝试将CS​​V_data列表导出到csv文件中。 以下是我的csv.py：

#coding=utf-8
from django.http import HttpResponse
from django.template import loader, Context
from demo.views import CSV_data


def output(request, filename):
    response = HttpResponse(mimetype='text/csv')
    response['Content-Disposition'] = 'attachment; filename=%s.csv' % filename

    t = loader.get_template('csv.txt')
    c = Context({
        'data': CSV_data,
    })
    response.write(t.render(c))
    return response

CSV_data是views.py中的变量，我尝试将其打印在模板中，该值确定。

 [(u'2012-06-01', [0, 0, 0]), ('2012-06-08', [0, 0, 0]), ('2012-06-15', [0, 0, 0]),    ('2012-06-22', [0, 0, 0]), ('2012-06-29', [0, 0, 0]), ('2012-07-06', [0, 0, 0]), ('2012-07-13', [0, 0, 0]), ('2012-07-20', [0, 0, 0]), ('2012-07-27', [0, 0, 0]), ('2012-08-03', [131, 164, 79.88]), ('2012-08-10', [110, 198, 55.56]), ('2012-08-17', [112, 197, 56.85]), ('2012-08-24', [147, 283, 51.94]), ('2012-08-31', [0, 306, 0.0]), ('2012-09-07', [418, 418, 100.0]), ('2012-09-14', [342, 342, 100.0]), ('2012-09-21', [732, 732, 100.0]), ('2012-09-28', [689, 689, 100.0]), ('2012-10-05', [775, 775, 100.0]), ('2012-10-12', [469, 469, 100.0]), ('2012-10-19', [477, 477, 100.0]), ('2012-10-26', [897, 897, 100.0]), ('2012-11-02', [216, 216, 100.0]), ('2012-11-09', [1046, 1046, 100.0]), ('2012-11-16', [840, 840, 100.0]), ('2012-11-23', [948, 948, 100.0])]

但是，生成的csv始终为空。

我试图将CSV_data定义添加到csv.py文件中，如下所示：

#coding=utf-8
from django.http import HttpResponse
from django.template import loader, Context

CSV_data = [(u'2012-06-01', [0, 0, 0]), ('2012-06-08', [0, 0, 0]), ('2012-06-15', [0, 0, 0]), ('2012-06-22', [0, 0, 0]), ('2012-06-29', [0, 0, 0]), ('2012-07-06', [0, 0, 0]), ('2012-07-13', [0, 0, 0]), ('2012-07-20', [0, 0, 0]), ('2012-07-27', [0, 0, 0]), ('2012-08-03', [131, 164, 79.88]), ('2012-08-10', [110, 198, 55.56]), ('2012-08-17', [112, 197, 56.85]), ('2012-08-24', [147, 283, 51.94]), ('2012-08-31', [0, 306, 0.0]), ('2012-09-07', [418, 418, 100.0]), ('2012-09-14', [342, 342, 100.0]), ('2012-09-21', [732, 732, 100.0]), ('2012-09-28', [689, 689, 100.0]), ('2012-10-05', [775, 775, 100.0]), ('2012-10-12', [469, 469, 100.0]), ('2012-10-19', [477, 477, 100.0]), ('2012-10-26', [897, 897, 100.0]), ('2012-11-02', [216, 216, 100.0]), ('2012-11-09', [1046, 1046, 100.0]), ('2012-11-16', [840, 840, 100.0]), ('2012-11-23', [948, 948, 100.0])]

def output(request, filename):
    response = HttpResponse(mimetype='text/csv')
    response['Content-Disposition'] = 'attachment; filename=%s.csv' % filename

    t = loader.get_template('csv.txt')
    c = Context({
        'data': CSV_data,
    })
    response.write(t.render(c))
    return response

然后，输出csv不为空。 因此，我认为从views.py导入CSV_data时出了点问题。

问题是我已测试视图中的CSV_data值正确。 那么怎么可能出问题了？

** * ** * ** * ** * ** * * 更新 * ** * ** * ** * ** * ** * ：

views.py中的原始代码如下：

 CSV_data = []
 def part_usage_result(request):
     ...(details omit)
     usageDictWeek = helper.getResultByWeek(modelName, spareCode, start, end) #returns a list
     CSV_data=usageDictWeek

我更改为：

 CSV_data = []
 def part_usage_result(request):
     ...(details omit)
     usageDictWeek = helper.getResultByWeek(modelName, spareCode, start, end) #returns a list
     for each in usageDictWeek:
         CSV_data.append(each)

现在，csv的内容是正确的。 还是不知道为什么会这样

Answer 1

由于您没有提供helper.getResultByWeek详细信息及其调用方式，因此我猜它返回带有列表值的全局变量，并且此变量在两者之间进行了修改。

 CSV_data = usageDictWeek

不要复制列表，而是创建对现有列表的另一个引用。 以后修改原始的usageDictWeek也会修改CSV_data。

当您改为

 CSV_data[:] = usageDictWeek 

创建了usageDictWeek的新副本并将其分配给CSV_data。

Answer 2

尝试使用关键字content_type而不是mimetype