如何获取最大列值计数。

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英文:

How to get the max column values count

问题

以下是您期望的输出:

    item_name            count
    Steak Salad Bowl     2
    Meat Salad Bowl      1
英文:

test dataframe is below

test=pd.DataFrame({'item_name':['Steak Salad Bowl','Steak Salad Bowl','Barbacoa Salad Bowl','Meat Salad Bowl'],'item_price':[9.39,9.39,9.19,9.39]})

grps = [grp for _, grp in test.groupby('item_name', sort=False)]
print(grps[0],grps[0].shape[0])

My Expected out

item_name            count
Steak Salad Bowl     2
Meat Salad Bowl      1

答案1

得分: 1

使用boolean indexing来根据max值进行筛选,然后使用Series.value_counts,对于DataFrame使用DataFrame.rename_axisDataFrame.reset_index

df = (test.loc[test['item_price'].eq(test['item_price'].max()), 'item_name']
          .value_counts()
          .rename_axis('item_name')
          .reset_index(name='count'))
print(df)

          item_name  count
0  Steak Salad Bowl      2
1   Meat Salad Bowl      1

或者对于计数,使用GroupBy.size

df = (test[test['item_price'].eq(test['item_price'].max())]
          .groupby('item_name')
          .size()
          .reset_index(name='count'))
print(df)

          item_name  count
0   Meat Salad Bowl      1
1  Steak Salad Bowl      2

以上是代码的翻译部分。

英文:

Use boolean indexing for filtering by max values, then Series.value_counts and for DataFrame DataFrame.rename_axis with DataFrame.reset_index:

df = (test.loc[test['item_price'].eq(test['item_price'].max()), 'item_name']
          .value_counts()
          .rename_axis('item_name')
          .reset_index(name='count'))
print (df)

          item_name  count
0  Steak Salad Bowl      2
1   Meat Salad Bowl      1

Or for count use GroupBy.size:

df = (test[test['item_price'].eq(test['item_price'].max())]
          .groupby('item_name')
          .size()
          .reset_index(name='count'))
print (df)
          item_name  count
0   Meat Salad Bowl      1
1  Steak Salad Bowl      2

答案2

得分: 1

使用nlargest(n)

test.nlargest(1, columns='item_price', keep='all')['item_name'].value_counts()

输出:

Steak Salad Bowl    2
Meat Salad Bowl     1
Name: item_name, dtype: int64
英文:

Using nlargest(n):

test.nlargest(1, columns='item_price', keep='all')['item_name'].value_counts()

Output:

Steak Salad Bowl    2
Meat Salad Bowl     1
Name: item_name, dtype: int64

答案3

得分: 1

使用 value_counts() 和 head() 和 reset_index() 和 rename()

pd.DataFrame(test['item_name'].value_counts().head(2).reset_index().rename(columns = {'index': 'item_name', 'item_name' : 'count'}))


输出

         item_name  count

0 牛排沙拉碗 2
1 巴巴科亚沙拉碗 1


<details>
<summary>英文:</summary>

Using value_counts() and head() and reset_index() and rename()

pd.DataFrame(test['item_name'].value_counts().head(2).reset_index().rename(columns = {'index': 'item_name', 'item_name' : 'count'}))


Output

         item_name  count

0 Steak Salad Bowl 2
1 Barbacoa Salad Bowl 1


</details>



huangapple
  • 本文由 发表于 2020年1月3日 14:07:38
  • 转载请务必保留本文链接:https://go.coder-hub.com/59573930.html
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