Pandas DataFrame，如何删除总和为 0 的所有列和行
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Pandas DataFrame, How do I remove all columns and rows that sum to 0
提问by Brig
I have a dataFrame with rows and columns that sum to 0.
我有一个行和列总和为 0 的数据框。
A B C D
0 1 1 0 1
1 0 0 0 0
2 1 0 0 1
3 0 1 0 0
4 1 1 0 1
The end result should be
最终结果应该是
A B D
0 1 1 1
2 1 0 1
3 0 1 0
4 1 1 1
Notice the rows and columns that only had zeros have been removed.
请注意，只有零的行和列已被删除。
回答by unutbu
df.loc[row_indexer, column_indexer]allows you to select rows and columns using boolean masks:
df.loc[row_indexer, column_indexer]允许您使用布尔掩码选择行和列：
In [88]: df.loc[(df.sum(axis=1) != 0), (df.sum(axis=0) != 0)]
Out[88]:
A B D
0 1 1 1
2 1 0 1
3 0 1 0
4 1 1 1
[4 rows x 3 columns]
df.sum(axis=1) != 0is True if and only if the row does not sum to 0.
df.sum(axis=1) != 0当且仅当行的总和不为 0 时为真。
df.sum(axis=0) != 0is True if and only if the column does not sum to 0.
df.sum(axis=0) != 0当且仅当列的总和不为 0 时为真。
回答by Ziggy Eunicien
building on Drop rows with all zeros in pandas data frameto avoid using the sum()
基础上删除行与Pandas数据帧全部为零，以避免使用总和（）
df = pd.DataFrame({'A': [1,0,1,0,1],
'B': [1,0,0,1,1],
'C': [0,0,0,0,0],
'D': [1,0,1,0,1]})
df.loc[(df!=0).any(1), (df!=0).any(0)]
A B D
0 1 1 1
2 1 0 1
3 0 1 0
4 1 1 1
回答by user3218971
This is my way to do it:
这是我的方法：
import pandas as pd
hl = []
df = pd.read_csv("my.csv")
l = list(df.columns.values)
for l in l:
if sum(df[l]) != 0:
hl.append(l)
df2 = df[hl]
to write reduced_Data:
写入reduced_Data：
df2.to_csv("my_reduced_data.csv")
It will only check columns but ignore Rows
它只会检查列但忽略行
