按两个值排序并保留两个最大值

Question

我有问题。我想创建一个图表。我想展示买家 b 和卖家 s 之间的区别。但我只想展示前两个国家。有没有一个选项可以过滤 b 和 s 并获得最高的 2？

数据框

   count country part
0     50      DE    b
1     20      CN    b
2     30      CN    s
3    100      BG    s
4      3      PL    b
5     40      BG    b
6      5      RU    s

代码

import matplotlib.pyplot as plt
import seaborn as sns
import pandas as pd
d = {'count': [50, 20, 30, 100, 3, 40, 5],
     'country': ['DE', 'CN', 'CN', 'BG', 'PL', 'BG', 'RU'],
     'part': ['b', 'b', 's', 's', 'b', 'b', 's']
    }
df = pd.DataFrame(data=d)


df_consignee_countries['party'] = 'consignee'
df_orders_countries['party'] = 'buyer'
df_party = pd.concat([df_consignee_countries, df_orders_countries], join="outer")

ax = sns.barplot(x="country", y="count", hue='part', data=df_party, palette='GnBu')
plt.legend(bbox_to_anchor=(1.05, 1), loc=2, borderaxespad=0.)
for p in ax.patches:
    ax.annotate(format(p.get_height(), '.1f'), 
                   (p.get_x() + p.get_width() / 2., p.get_height()), 
                   ha = 'center', va = 'center', 
                   xytext = (0, 9), 
                   textcoords = 'offset points')

我想要的

   count country part
0     50      DE    b
2     30      CN    s
3    100      BG    s
5     40      BG    b

Answer 1

您首先需要对值进行排序，然后每组取 2 行：

>>> df.sort_values('count', ascending=False).groupby('part').head(2)
   count country part
3    100      BG    s
0     50      DE    b
5     40      BG    b
2     30      CN    s

Answer 2

你要这个吗？ :

df_b=df.loc[df['part']=='b',:].sort_values(by='count',ascending=False).head(n=2)
df_b=df_b.append(df.loc[df['part']=='s',:].sort_values(by='count',ascending=False).head(n=2))
df_b

按两个值排序并保留两个最大值

Sorting by two values and keeping the two highest values

python

dataframe

pandas

seaborn