pandas 熊猫绘制多个类别线
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Pandas plot multiple category lines
提问by Craig
Say I have the following data...
假设我有以下数据...
date Score category
2017-01-01 50.0 1
2017-01-01 590.0 2
2017-01-02 30.0 1
2017-01-02 210.4 2
2017-01-03 11.0 1
2017-01-03 50.3 2
So on a daily basis, I have multiple categories, each being assigned a score. Here's my code so far...
所以每天，我有多个类别，每个类别都有一个分数。到目前为止，这是我的代码...
vals = [{'date': '2017-01-01', 'category': 1, 'Score': 50},
{'date': '2017-01-01', 'category': 2, 'Score': 590},
{'date': '2017-01-02', 'category': 1, 'Score': 30},
{'date': '2017-01-02', 'category': 2, 'Score': 210.4},
{'date': '2017-01-03', 'category': 1, 'Score': 11},
{'date': '2017-01-03', 'category': 2, 'Score': 50.3}]
df = pd.DataFrame(vals)
df.date = pd.to_datetime(df['date'], format='%Y-%m-%d')
df.set_index(['date'],inplace=True)
Which results in a bizarre plot as below.
这导致了一个奇怪的情节如下。
I'd like to have multiple lines, one for each category, and the date on the X-axis - how would I do this?
我想要多行，每个类别一行，以及 X 轴上的日期 - 我该怎么做？
回答by Vaishali
You can use groupby and plot
您可以使用 groupby 和 plot
fig, ax = plt.subplots()
for label, grp in df.groupby('category'):
grp.plot(x = grp.index, y = 'Score',ax = ax, label = label)
回答by Scott Boston
Let's try using axes with ax=axand parameter secondary_y=True:
让我们尝试使用带有ax=ax和参数的轴secondary_y=True：
ax = df.plot(x=df.index, y='Score')
df.plot(x=df.index, y='category', secondary_y=True, ax=ax)
Output:
输出：
Or if @Vaishali plot is what you want you can do it with this one-liner.
或者如果@Vaishali 情节是你想要的，你可以用这个单线来做。
df.set_index('category',append=True).unstack()['Score'].plot()
Output:
输出：
