小编joh*_*ohn的帖子

我有以下内容:

answers = Answer.objects.filter(id__in=[answer.id for answer in answer_set.answers.all()])

然后:

for i in range(len(answers)):
    # iterate through all existing QuestionAnswer objects
    for existing_question_answer in existing_question_answers:
        # if an answer is already associated, remove it from the
        # list of answers to save
        if answers[i].id == existing_question_answer.answer.id:
            answers.remove(answers[i])           # doesn't work
            existing_question_answers.remove(existing_question_answer)

我收到一个错误:

'QuerySet' object has no attribute 'remove'

我已经尝试了各种将QuerySet转换为标准集或列表.什么都行不通.

如何从QuerySet中删除一个项目,以便它不会从数据库中删除它,并且不会返回一个新的QuerySet(因为它在一个不起作用的循环中)？

我正在使用matjlotlib和django.我正在尝试创建条形图.

我跟着食谱,但我有一个灰色的矩形盒子.

现在我使用以下代码,并有一个标题和轴.

如何在图中添加条形图？目前轴内没有实际数据.

这是我的图表代码:

from matplotlib.backends.backend_agg import FigureCanvasAgg 
from matplotlib.figure import Figure
import matplotlib.pyplot as plt

class Chart(object):

    ## Creates a bar chart of the given data
    @staticmethod
    def bar(data):
        figure = Figure(figsize=(6,6))
        ax = figure.add_axes([0.1, 0.1, 0.8, 0.8])
        labels = 'Frogs', 'Hogs', 'Dogs', 'Logs'
        fracs = [15, 30, 45, 10]
        explode=(0, 0.05, 0, 0)
        plt.pie(fracs, explode=explode, labels=labels, autopct='%1.1f%%', shadow=True)
        figure.suptitle('Raining Hogs and Dogs', fontsize=14)

        canvas = FigureCanvasAgg(figure)

        return canvas

在我看来,我有:

canvas = Chart.bar(results)

# turn the …