英文:
How to use mapped values for numerical chart axis ticks
问题
我有一个变量 df，它包含一些类似于 pandas 中这样的数据：
Date Number Letter2017-10-31 2 B2019-08-31 1 A2021-11-30 3 C...
我想在 seaborn 中绘制这个数据，所以我使用了如下的代码：
sb.lineplot(data=df, x='Date', y='Number')plt.show()
我得到了一个整齐的线形图，看起来类似于这个样子：
但是，我希望 y 轴的刻度标签保持数字列的数值顺序，但显示为字母列的标签。例如，与其 y 轴显示为 10 到 17，我希望 y 轴显示为 j 到 t。
是否可以通过 sb.lineplot 的参数实现这一点，还是我需要另一种方法？
英文:
Say I have a variable, df, that contains some data that looks like this in pandas
Date Number Letter2017-10-31 2 B2019-08-31 1 A2021-11-30 3 C...
I'd like to chart this out in seaborn, so I use some code like this
sb.lineplot(data=df, x=Date, y=Number)plt.show()
And I get an orderly line chart that looks something like this
However, i'd like to have the y axis tick labels to preserve the numerical order of the number column, but present as labels from the letter column. For instance, instead of the y axis being 10 - 17 as above, i'd like the y axis to read j - t.
Is there a way to implement that through the sb.lineplot arguments, or would I need another way?
答案1
得分: 3
了解，您可以使用 FixedLocator 和 FixedFormatter：
import matplotlib.ticker as tickerax = sb.lineplot(data=df, x='日期', y='数量')ax.yaxis.set_major_locator(ticker.FixedLocator(df['数量']))ax.yaxis.set_major_formatter(ticker.FixedFormatter(df['字母']))plt.show()
输出：
英文:
IIUC, you can use FixedLocator and FixedFormatter:
import matplotlib.ticker as tickerax = sb.lineplot(data=df, x='Date', y='Number')ax.yaxis.set_major_locator(ticker.FixedLocator(df['Number']))ax.yaxis.set_major_formatter(ticker.FixedFormatter(df['Letter']))plt.show()
Output:
答案2
得分: 1
- 在y轴上绘制
'Letter'更为直观。 - 如果y轴上的值需要特定顺序，请使用
pd.Categorical设置'Letter'列。categories=sorted(df.Letter, reverse=True)，将reverse设置为False，以将A放在y轴的顶部。
- 在
python 3.11.3、pandas 2.0.2、matplotlib 3.7.1、seaborn 0.12.2中测试通过
import pandas as pdimport seaborn as sns # 这是标准别名import matplotlib.pyplot as plt# 示例数据data = {'Date': ['2017-10-31', '2019-08-31', '2021-11-30'], 'Number': [2, 1, 3], 'Letter': ['B', 'A', 'C']}df = pd.DataFrame(data)# 确认Date列是日期日期数据类型df.Date = pd.to_datetime(df.Date).dt.date# 对Letter列进行排序df.Letter = pd.Categorical(df.Letter, categories=sorted(df.Letter, reverse=True))# 绘图fig = plt.figure(figsize=(10, 6))ax = sns.lineplot(data=df, x='Date', y='Letter')
英文:
- It's more straightforward to plot
'Letter'on the y-axis. - If the values on the y-axis require a specific order, then set the
'Letter'column withpd.Categorical.categories=sorted(df.Letter, reverse=True), setreverse=Falseto haveAat the top of the y-axis.
- Tested in
python 3.11.3,pandas 2.0.2,matplotlib 3.7.1,seaborn 0.12.2
import pnadas as pdimport seaborn as sns # this is the standard aliasimport matplotlib.pyplot as plt# sample datadata = {'Date': ['2017-10-31', '2019-08-31', '2021-11-30'], 'Number': [2, 1, 3], 'Letter': ['B', 'A', 'C']}df = pd.DataFrame(data)# confirm the Date column is a datetime date dtypedf.Date = pd.to_datetime(df.Date).dt.date# order the Letter columndf.Letter = pd.Categorical(df.Letter, categories=sorted(df.Letter, reverse=True))# plotfig = plt.figure(figsize=(10, 6))ax = sns.lineplot(data=df, x='Date', y='Letter')
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