[英]Edit data in a python pandas filter and apply it to the original data frame
我试图弄清楚如何过滤pandas中的数据,然后为符合筛选条件的项目的列中的所有行分配值,并使其影响原始数据框。 这是我迄今为止最接近的尝试,但它抛出了许多信息警告:
import pandas as pd
df = pd.read_csv('http://www.sharecsv.com/dl/9096d32f98aa0ac671a1cca16fa43be8/SalesJan2009.csv')
df['Zone'] = ''
zone1 = df[(df['Latitude'] > 0) & (df['Latitude'] > 0)]
zone2 = df[(df['Latitude'] < 0) & (df['Latitude'] > 0)]
zone3 = df[(df['Latitude'] > 0) & (df['Latitude'] < 0)]
zone4 = df[(df['Latitude'] < 0) & (df['Latitude'] < 0)]
zone1[['Zone']] = zone1[['Zone']] = 1
zone2[['Zone']] = zone1[['Zone']] = 2
zone3[['Zone']] = zone1[['Zone']] = 3
zone4[['Zone']] = zone1[['Zone']] = 4
df
这根本不会影响原始数据帧,但它会设置过滤子集中的值。
我假设我可能需要过滤掉满足我的每个过滤器的所有内容并将其从原始过滤器中删除,然后将更改连接回原始版本?
这是一个随机数据集,用于说明我要做的事情,但我的实际数据集中的数据不符合任何过滤条件,我需要将这些数据保持为未知数,因为我不会消耗所有行,因为我会使用这个例。
我试图避免不得不遍历每一行并检查每一行的标准,所以如果有人知道如何实现这一点,我将非常感激!
IIUC,你想做这样的事情:
zone1 = (df['Latitude'] > 0) & (df['Longitude'] > 0)
zone2 = (df['Latitude'] < 0) & (df['Longitude'] > 0)
zone3 = (df['Latitude'] > 0) & (df['Longitude'] < 0)
zone4 = (df['Latitude'] < 0) & (df['Longitude'] < 0)
df['Zone'] = np.select([zone1,zone2,zone3,zone3],['Zone 1','Zone 2', 'Zone 3','Zone 4'])
输出:
Transaction_date Product Price Payment_Type Name \
0 1/2/09 6:17 Product1 1200 Mastercard carolina
1 1/2/09 4:53 Product1 1200 Visa Betina
2 1/2/09 13:08 Product1 1200 Mastercard Federica e Andrea
3 1/3/09 14:44 Product1 1200 Visa Gouya
4 1/4/09 12:56 Product2 3600 Visa Gerd W
City State Country Account_Created \
0 Basildon England United Kingdom 1/2/09 6:00
1 Parkville MO United States 1/2/09 4:42
2 Astoria OR United States 1/1/09 16:21
3 Echuca Victoria Australia 9/25/05 21:13
4 Cahaba Heights AL United States 11/15/08 15:47
Last_Login Latitude Longitude Zone
0 1/2/09 6:08 51.500000 -1.116667 Zone 3
1 1/2/09 7:49 39.195000 -94.681940 Zone 3
2 1/3/09 12:32 46.188060 -123.830000 Zone 3
3 1/3/09 14:22 -36.133333 144.750000 Zone 2
4 1/4/09 12:45 33.520560 -86.802500 Zone 3
您错过了两个条件都在检查Latitude ,您应该检查.loc
以便您学习如何以正确的方式更改数据框的部分值。
import pandas as pd
df = pd.read_csv('http://www.sharecsv.com/dl/9096d32f98aa0ac671a1cca16fa43be8/SalesJan2009.csv')
df['Zone'] = ''
zone1 = (df['Latitude'] > 0) & (df['Longitude'] > 0)
zone2 = (df['Latitude'] < 0) & (df['Longitude'] > 0)
zone3 = (df['Latitude'] > 0) & (df['Longitude'] < 0)
zone4 = (df['Latitude'] < 0) & (df['Longitude'] < 0)
df.loc[zone1, 'Zone'] = 1
df.loc[zone2, 'Zone'] = 2
df.loc[zone3, 'Zone'] = 3
df.loc[zone4, 'Zone'] = 4
df
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