英文:
Python to add data label on linechart from Matplotlib and Pandas GroupBy
问题
以下是您的代码的翻译部分：
# 导入需要的库import matplotlib.pyplot as pltimport pandas as pdfrom io import StringIO# 创建包含数据的CSV字符串csvfile = StringIO("""Name Year - Month ScoreMike 2022-09 192Mike 2022-08 708Mike 2022-07 140Mike 2022-05 144Mike 2022-04 60Mike 2022-03 108Kate 2022-07 19850Kate 2022-06 19105Kate 2022-05 23740Kate 2022-04 19780Kate 2022-03 15495Peter 2022-08 51Peter 2022-07 39Peter 2022-06 49Peter 2022-05 49Peter 2022-04 79Peter 2022-03 13Lily 2022-11 2David 2022-11 3David 2022-10 6David 2022-08 2""")# 从CSV读取数据df = pd.read_csv(csvfile, sep='\t', engine='python')# 按 "Name" 列分组for group_name, sub_frame in df.groupby("Name"):if sub_frame.shape[0] >= 2:# 对子数据框按 "Year - Month" 列排序sub_frame_sorted = sub_frame.sort_values('Year - Month')# 创建线图line_chart = sub_frame_sorted.plot("Year - Month", "Score")# 添加数据标签labels = sub_frame_sorted['Score']for i, label in enumerate(labels):line_chart.annotate(label, (sub_frame_sorted['Year - Month'].iloc[i], sub_frame_sorted['Score'].iloc[i]), ha='center')# 显示图表plt.show()
数据标签的错误已被修复。在循环中，我们使用了enumerate函数来遍历数据标签，以确保它们正确地与数据点匹配。
英文:
I am hoping to add data labels to a line chart produced by Matplotlib from Pandas GroupBy.
import matplotlib.pyplot as pltimport pandas as pdfrom io import StringIOcsvfile = StringIO("""Name Year - Month ScoreMike 2022-09 192Mike 2022-08 708Mike 2022-07 140Mike 2022-05 144Mike 2022-04 60Mike 2022-03 108Kate 2022-07 19850Kate 2022-06 19105Kate 2022-05 23740Kate 2022-04 19780Kate 2022-03 15495Peter 2022-08 51Peter 2022-07 39Peter 2022-06 49Peter 2022-05 49Peter 2022-04 79Peter 2022-03 13Lily 2022-11 2David 2022-11 3David 2022-10 6David 2022-08 2""")df = pd.read_csv(csvfile, sep = '\t', engine='python')for group_name, sub_frame in df.groupby("Name"):if sub_frame.shape[0] >= 2:sub_frame_sorted = sub_frame.sort_values('Year - Month') # sort the data-frame by a columnline_chart = sub_frame_sorted.plot("Year - Month", "Score")label = sub_frame_sorted['Score']line_chart.annotate(label, (sub_frame_sorted['Year - Month'], sub_frame_sorted['Score']), ha='center')plt.show()
The 2 lines for data labels throw an error:
ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().
How can I have them corrected?
答案1
得分: 1
问题应该出现在你的for循环内部。
你可以用这段代码替换你的代码：
for group_name, sub_frame in df.groupby("Name"):if sub_frame.shape[0] >= 2:sub_frame_sorted = sub_frame.sort_values('Year - Month')line_chart = sub_frame_sorted.plot("Year - Month", "Score")for x, y in zip(sub_frame_sorted["Year - Month"], sub_frame_sorted["Score"]):label = "{:.0f}".format(y) # 将标签格式化为字符串line_chart.annotate(label, (x, y), textcoords="offset points", xytext=(0, 10), ha='center')
如果你遇到关于'Year-Month'的错误，你应该使用to_datetime()方法进行转换。
请告诉我这是否有帮助。谢谢。
英文:
So, the problem should be inside your for loop.
You can replace your code by this one:
for group_name, sub_frame in df.groupby("Name"):if sub_frame.shape[0] >= 2:sub_frame_sorted = sub_frame.sort_values('Year - Month')line_chart = sub_frame_sorted.plot("Year - Month", "Score")for x, y in zip(sub_frame_sorted["Year - Month"], sub_frame_sorted["Score"]):label = "{:.0f}".format(y) # format the label as a stringline_chart.annotate(label, (x, y), textcoords="offset points", xytext=(0,10), ha='center')
And also if you face error regarding 'Year-Month' you should convert that using to_datetime() method.
Please let me know if this helps. Thanks.
答案2
得分: 1
代码中提到错误是在annotate()函数中。sub_frame_sorted是一个数据框，你需要使用for循环来获取其中的每个项目，然后再使用annotate。此外，x轴是年份-月份，被视为字符串，可能会出现问题。因此，你只需要使用索引。我使用了0、1、2...来表示索引，使用i。这应该可以工作...如果你认为文本与线重叠，可以添加一个小的偏移量。
希望这是你要找的内容。
更新的代码
for group_name, sub_frame in df.groupby("Name"):if sub_frame.shape[0] >= 2:sub_frame_sorted = sub_frame.sort_values('Year - Month') # 按列对数据框进行排序line_chart = sub_frame_sorted.plot("Year - Month", "Score", legend=False)i = 0for ix, vl in sub_frame_sorted.iterrows():line_chart.annotate(vl['Score'], (i, vl['Score']), ha='center')i = i + 1plt.show()
输出图表
英文:
As the error says that the problem is in the annotate(). The sub_frame_sorted is a dataframe and you need to use a for loop to get each of the items within it before using annotate. Also, the x-axis is year-month, which is seen as string and you will run into issues. So, you need to just use index. I have used 0,1,2... using i. This should work... you can add a small offset if you think the text is overlapping a line
Hope this is what you are looking for.
Updated code
for group_name, sub_frame in df.groupby("Name"):if sub_frame.shape[0] >= 2:sub_frame_sorted = sub_frame.sort_values('Year - Month') # sort the data-frame by a columnline_chart = sub_frame_sorted.plot("Year - Month", "Score", legend=False)i=0for ix, vl in sub_frame_sorted.iterrows():line_chart.annotate(vl['Score'], (i, vl['Score']), ha='center')i=i+1plt.show()
Output plots
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