正在复制Pandas DataFrame中其他单元格的值

Question

因此，我想要完成的是，每次在数据帧中发现一行缺少日期和前五列的其余部分时，复制其上一行的值。示例：

0| Date      | Name | Amount | Address
1| 12/04/2018| Pepe | $1.00  | Avenue 1
2| NaT       | NaN  |  NaN   |  NaN (In this line i need the values of the line above)
3| 1/04/2018 | Tito |  $3.00 |  Avenue 2

for file in files:
fileName = os.path.splitext(file)[0]
if fileName == 'xxxxxxx (copy)':
df = pd.read_excel(file)
for index, row in df.iterrows():
if pd.isna(df['Date'] 'And the rest of the 5 columns'):
#Copy the values of the line above it

Answer 1

使用ffill()结转以上行。

示例：

# Given
df = pd.DataFrame({'word':['Alpha', np.NaN, 'Charlie'],
'Percentage 1':[10, np.NaN, 0],
'Percentage 2': [5, np.NaN, 4]})
df
word    Percentage 1    Percentage 2
0   Alpha   10.0             5.0
1   NaN     NaN              NaN
2   Charlie 0.0              4.0
df = df.ffill()
word     Percentage 1    Percentage 2
0  Alpha    10.0            5.0
1  Alpha    10.0            5.0
2  Charlie  0.0             4.0

Answer 2

所以我使用ffill(正向填充(方法来解决它，下面是代码：

for file in files:
fileName = os.path.splitext(file)[0]
if fileName == 'File1':
df = pd.read_excel(file)
new_df = df.fillna(method="ffill")
writer = pd.ExcelWriter('File1.xlsx', engine='xlsxwriter')
new_df.to_excel(writer, 'Sheet 1')
writer.save()