问题描述
我有一个带有地址列的大型 DataFrame:
I have a large DataFrame with an address column:
data addr 0 0.617964 IN,Krishnagiri,635115 1 0.635428 IN,Chennai,600005 2 0.630125 IN,Karnal,132001 3 0.981282 IN,Jaipur,302021 4 0.715813 IN,Chennai,600005 ...
我写了下面的函数,用地址的经纬度坐标替换地址:
and I've written the following function to replace the address with the longitude and latitude coordinates of the address:
from geopy.geocoders import Nominatim geo_locator = Nominatim(user_agent="MY_APP_ID") def get_coordinates(addr): location = geo_locator.geocode(addr) if location is not None: return pd.Series({'lat': location.latitude, 'lon': location.longitude}) location = geo_locator.geocode(addr.split(',')[0]) if location is not None: return pd.Series({'lat': location.latitude, 'lon': location.longitude}) return pd.Series({'lat': -1, 'lon': -1})
然后在地址列上调用pandas apply方法,并将结果连接到DF的末尾而不是地址列:
Then calling pandas apply method on the address column, and concatinating the result to the end of the DF instead of the address column:
df = pd.concat([df, df.addr.apply(get_coordinates)], axis=1).drop(['addr'], axis=1)
但是,由于 get_coordinates 调用了第 3 方 API,因此失败:geopy.exc.GeocoderTimedOut: Service timed out
However, since the get_coordinates calls a 3rd party API it fails on: geopy.exc.GeocoderTimedOut: Service timed out
如何限制请求以确保在继续下一个值之前得到响应?
How do I throttle the requests to make sure I got a response before continuing to the next value?
更新:
为了进一步改进,我想仅在唯一值上调用 API,即:如果地址 IN,Krishnagiri,635115 在我的 DataFrame 中出现 20 次,我只想调用一次并应用所有 20 次出现的结果.
Update:
For further improvements, I would like to call the API only on unique values, i.e: if the address IN,Krishnagiri,635115 appears 20 times in my DataFrame, I would like to call it only once and apply the results to all 20 occurrences.
更新 2:
日志 + 堆栈跟踪,用于@Andrew Lavers 代码:
Update 2:
Log + Stack trace, for @Andrew Lavers code:
... Fetched Gandipet, Khanapur, Rangareddy District, Telangana, 500075, India Fetched Jaipur Municipal Corporation, Jaipur, Rajasthan, 302015, India Fetched Chennai, Chennai district, Tamil Nadu, India Exception from geolocator: Fake exception for testing Backing off for 1 seconds. Exception from geolocator: Fake exception for testing Backing off for 3 seconds. Fetched None Traceback (most recent call last): File "/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/geopy/geocoders/base.py", line 344, in _call_geocoder page = requester(req, timeout=timeout, **kwargs) File "/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 526, in open response = self._open(req, data) File "/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 544, in _open '_open', req) File "/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 504, in _call_chain result = func(*args) File "/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 1361, in https_open context=self._context, check_hostname=self._check_hostname) File "/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 1321, in do_open r = h.getresponse() File "/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py", line 1331, in getresponse response.begin() File "/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py", line 297, in begin version, status, reason = self._read_status() File "/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py", line 258, in _read_status line = str(self.fp.readline(_MAXLINE + 1), "iso-8859-1") File "/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/socket.py", line 586, in readinto return self._sock.recv_into(b) File "/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/ssl.py", line 1002, in recv_into return self.read(nbytes, buffer) File "/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/ssl.py", line 865, in read return self._sslobj.read(len, buffer) File "/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/ssl.py", line 625, in read v = self._sslobj.read(len, buffer) socket.timeout: The read operation timed out During handling of the above exception, another exception occurred: Traceback (most recent call last): File "/Users/...//tmp.py", line 89, in <module> df.addr.apply(get_coordinates) File "/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/pandas/core/series.py", line 3194, in apply mapped = lib.map_infer(values, f, convert=convert_dtype) File "pandas/_libs/src/inference.pyx", line 1472, in pandas._libs.lib.map_infer File "/Users/...//tmp.py", line 76, in get_coordinates location = geo_locator.geocode(addr.split(',')[0]) File "/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/geopy/geocoders/osm.py", line 307, in geocode self._call_geocoder(url, timeout=timeout), exactly_one File "/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/geopy/geocoders/base.py", line 371, in _call_geocoder raise GeocoderTimedOut('Service timed out') geopy.exc.GeocoderTimedOut: Service timed out Process finished with exit code 1
推荐答案
这里有一些测试代码可能会有所帮助.1) 对 Api 指定的简单速率限制(Nominatum 似乎是每秒 1 次,但我的成功率低至 0.1 秒).2) 字典中的简单结果缓存,可通过测试参数控制 3) 具有乘法减速和线性加速的重试循环.(减速快,加速更慢) 4)伪造错误的测试异常
Here is some tested code that may help. 1) Simple rate limiting to what the Api specifies (Nominatum appears to be 1 per second but i got success as low as 0.1 seconds). 2) Simple result caching in a dictionary, controllable by parameter for testing 3) Retry loop with multiplicative slowdown and linear speedup. (slows down fast, speeds up more slowly) 4) Test exception for faking errors
我无法复制您遇到的问题 - 可能是由于您使用 API 的路径.
I cannot replicate the issues you are experiencing - likely due to your path to the API.
更健壮的策略可能是构建本地持久性缓存并继续重试,直到构建完整的批次.缓存可以是一个以 csv 格式写入文件的 pandas 数据帧.整个伪代码类似于.
A more robust strategy may to build a local persistence cache and continue to retry until the full batch is built. The cache could be a pandas dataframe written as csv to file. The overall pseudo code is something like.
repeat until all addresses are in the cache cache = pd.read_csv("cache.csv) addressess_to_get = addresses in df that are not in cache for batch of n addresses in addresses_to_get: cache.add(get_location(addr)) cache.write_csv("cache.csv")
这是测试代码
import datetime import time import pandas as pd from geopy.geocoders import Nominatim geo_locator = Nominatim(user_agent="notarealemail@gmail.com") # Define the rate limit function and associated global variable last_time = datetime.datetime.now() backoff_time = 0 def rate_limit(min_interval_seconds = .1): global last_time sleep = min_interval_seconds - (datetime.datetime.now() - last_time).total_seconds() if sleep > 0 : print(f'Sleeping for {sleep} seconds') time.sleep(sleep) last_time = datetime.datetime.now() # make a cache dictionary keyed by address geo_cache = {} backoff_seconds = 0 def get_coordinates_with_retry(addr): # Return coords from global cache if it exists global backoff_seconds # set the backoff intital values and factors max_backoff_seconds = 60 backoff_exponential = 2 backoff_linear = 2 # rate limited API call rate_limit() # Retry until max_back_seconds is reached while backoff_seconds < max_backoff_seconds: # backoff up to this time if backoff_seconds > 0: print(f"Backing off for {backoff_seconds} seconds.") time.sleep(backoff_seconds) try: location = geo_locator.geocode(addr) # REMOVE THIS: fake an error for testing #import random #if random.random() < .3: # raise(Exception("Fake exception for testing")) # Success - so reduce the backoff linearly print (f"Fetched {location} for address {addr}") backoff_seconds = backoff_seconds - backoff_linear if backoff_seconds > backoff_linear else 0 break except Exception as e: print(f"Exception from geolocator: {e}") # Backoff exponentially backoff_seconds = 1 + backoff_seconds * backoff_exponential if backoff_seconds > max_backoff_seconds: raise Exception("Max backoff reached ") return(location) def get_coordinates(addr, useCache = True): # Return from cache if previously loaded global geo_cache if addr in geo_cache: return geo_cache[addr] # Attempt using the full address location = get_coordinates_with_retry(addr) # Attempt using the first part only if None found if location is not None: result = pd.Series({'lat': location.latitude, 'lon': location.longitude}) else : print (f"Trying split address for address {addr}") location = get_coordinates_with_retry(addr.split(',')[0]) if location is not None: result = pd.Series({'lat': location.latitude, 'lon': location.longitude}) else: result = pd.Series({'lat': -1, 'lon': -1}) # assign to cache if useCache: geo_cache[addr] = result return(result) # Use the test data df = pd.DataFrame({'addr' : [ 'IN,Krishnagiri,635115', 'IN,Chennai,600005', 'IN,Karnal,132001', 'IN,Jaipur,302021', 'IN,Chennai,600005']}) # repeat the test data to make alarger set df = pd.concat([df, df, df, df, df, df, df, df, df, df]) df.addr.apply(get_coordinates) print(f"Address cache contains {len(geo_cache)} address locations.")