填充 Pandas Dataframe 列中缺失的日期值
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Fill the missing date values in a Pandas Dataframe column
提问by User456898
I'm using Pandas to store stock prices data using Data Frames. There are 2940 rows in the dataset. The Dataset snapshot is displayed below:
我正在使用 Pandas 使用 Data Frames 存储股票价格数据。数据集中有 2940 行。数据集快照如下所示：
The time series data does not contain the values for Saturday and Sunday. Hence missing values have to be filled.
Here is the code I've written but it is not solving the problem:
时间序列数据不包含周六和周日的值。因此必须填充缺失值。
这是我写的代码，但它没有解决问题：
import pandas as pd
import numpy as np
import os
os.chdir('C:/Users/Admin/Analytics/stock-prices')
data = pd.read_csv('stock-data.csv')
# PriceDate Column - Does not contain Saturday and Sunday stock entries
data['PriceDate'] = pd.to_datetime(data['PriceDate'], format='%m/%d/%Y')
data = data.sort_index(by=['PriceDate'], ascending=[True])
# Starting date is Aug 25 2004
idx = pd.date_range('08-25-2004',periods=2940,freq='D')
data = data.set_index(idx)
data['newdate']=data.index
newdate=data['newdate'].values # Create a time series column
data = pd.merge(newdate, data, on='PriceDate', how='outer')
How to fill the missing values for Saturday and Sunday?
如何填补周六和周日的缺失值？
回答by jezrael
I think you can use resamplewith ffillor bfill, but before set_indexfrom column PriceDate:
我认为您可以使用resamplewithffill或bfill，但在set_indexfrom column之前PriceDate：
print (data)
ID PriceDate OpenPrice HighPrice
0 1 6/24/2016 1 2
1 2 6/23/2016 3 4
2 2 6/22/2016 5 6
3 2 6/21/2016 7 8
4 2 6/20/2016 9 10
5 2 6/17/2016 11 12
6 2 6/16/2016 13 14
data['PriceDate'] = pd.to_datetime(data['PriceDate'], format='%m/%d/%Y')
data = data.sort_values(by=['PriceDate'], ascending=[True])
data.set_index('PriceDate', inplace=True)
print (data)
ID OpenPrice HighPrice
PriceDate
2016-06-16 2 13 14
2016-06-17 2 11 12
2016-06-20 2 9 10
2016-06-21 2 7 8
2016-06-22 2 5 6
2016-06-23 2 3 4
2016-06-24 1 1 2
data = data.resample('D').ffill().reset_index()
print (data)
PriceDate ID OpenPrice HighPrice
0 2016-06-16 2 13 14
1 2016-06-17 2 11 12
2 2016-06-18 2 11 12
3 2016-06-19 2 11 12
4 2016-06-20 2 9 10
5 2016-06-21 2 7 8
6 2016-06-22 2 5 6
7 2016-06-23 2 3 4
8 2016-06-24 1 1 2
data = data.resample('D').bfill().reset_index()
print (data)
PriceDate ID OpenPrice HighPrice
0 2016-06-16 2 13 14
1 2016-06-17 2 11 12
2 2016-06-18 2 9 10
3 2016-06-19 2 9 10
4 2016-06-20 2 9 10
5 2016-06-21 2 7 8
6 2016-06-22 2 5 6
7 2016-06-23 2 3 4
8 2016-06-24 1 1 2
