合并pandas中的NaN行而不丢失单元格值

import pandas as pd

# 创建一个包含NaN值的DataFrame
data = {'A': [1, 2, None, 4],
        'B': [5, None, 7, 8],
        'C': [None, 10, 11, 12]}
df = pd.DataFrame(data)

# 使用指定的值填充NaN
df_filled = df.fillna(0)
print(df_filled)

# 使用前向填充填充NaN
df_ffilled = df.fillna(method='ffill')
print(df_ffilled)

# 使用后向填充填充NaN
df_bfilled = df.fillna(method='bfill')
print(df_bfilled)

     A    B     C
0  1.0  5.0   0.0
1  2.0  0.0  10.0
2  0.0  7.0  11.0
3  4.0  8.0  12.0

     A    B     C
0  1.0  5.0   NaN
1  2.0  5.0  10.0
2  2.0  7.0  11.0
3  4.0  8.0  12.0

     A    B     C
0  1.0  5.0  10.0
1  2.0  7.0  10.0
2  4.0  7.0  11.0
3  4.0  8.0  12.0