如何对多列 pandas 应用一个函数？

Question

我需要计算 pandas 数据框中 2 个邮政编码之间的距离。

我正在使用 pgeocode 库来计算 2 个英国邮政编码之间的距离

enter image description here

dist = samp.apply(lambda x:dist.query_postal_code(x['a'],x['b']), axis=1) -

它不工作（未正确调用 DataFrame 构造函数！）错误

Answer 1

您需要参考数据库中的 column-names 才能访问基础值。

改为

dist = samp.apply(lambda x:dist.query_postal_code(x['Postcode.x'],x['Postcode.y']), axis=1)

Answer 2

一切尽在你的准备

从网络服务获取地理数据
将其准备为元组并生成您的组合
计算距离

import geopy.distance, requests
import pandas as pd

# a few post codes..
df = pd.DataFrame({'Name': ['BROAD STREET DENTAL SURGERY',
  'KINGTON SURGERY',
  'ALTON STREET SURGERY'],
 'PostCode': ['HR4 9AR', 'HR5 3EA', 'HR9 5AB']})


# get geo data for postcodes
dfgeo = (pd.json_normalize(requests.post("http://api.postcodes.io/postcodes", 
               json={"postcodes":df.PostCode.unique().tolist()}).json()["result"])
         # make long / lat a tuple
         .assign(geo=lambda d: d.loc[:,["result.longitude","result.latitude"]].apply(lambda r: tuple(r), axis=1))
         .loc[:,["result.postcode","geo"]]
         .rename(columns={"result.postcode":"PostCode"})
        )

# merge geo data with original postcode data
df = df.merge(dfgeo, on="PostCode")

# generate all combinations, remove to self...
dfd = (df.assign(foo=1).merge(df.assign(foo=1), on="foo", suffixes=("_addr1","_addr2"))
 .drop(columns=["foo"]).loc[lambda d: d.PostCode_addr1!=d.PostCode_addr2]
 # all prep done,  let's calc distance
 .assign(miles=lambda d: d.apply(lambda r: geopy.distance.distance(r["geo_addr1"], r["geo_addr2"]).miles, axis=1))
)

	Name_addr1	PostCode_addr1	geo_addr1	Name_addr2	PostCode_addr2	geo_addr2	miles
1	BROAD STREET DENTAL SURGERY	HR4 9AR	(-2.717611, 52.055269)	KINGTON SURGERY	HR5 3EA	(-3.022556, 52.199361)	23.1971
2	BROAD STREET DENTAL SURGERY	HR4 9AR	(-2.717611, 52.055269)	ALTON STREET SURGERY	HR9 5AB	(-2.582971, 51.911934)	13.5525
3	KINGTON SURGERY	HR5 3EA	(-3.022556, 52.199361)	BROAD STREET DENTAL SURGERY	HR4 9AR	(-2.717611, 52.055269)	23.1971
5	KINGTON SURGERY	HR5 3EA	(-3.022556, 52.199361)	ALTON STREET SURGERY	HR9 5AB	(-2.582971, 51.911934)	36.1468
6	ALTON STREET SURGERY	HR9 5AB	(-2.582971, 51.911934)	BROAD STREET DENTAL SURGERY	HR4 9AR	(-2.717611, 52.055269)	13.5525
7	ALTON STREET SURGERY	HR9 5AB	(-2.582971, 51.911934)	KINGTON SURGERY	HR5 3EA	(-3.022556, 52.199361)	36.1468

如何对多列 pandas 应用一个函数？

How to apply a function for multiple columns pandas?

python

apply

pandas