python-2.x

问题 In python2.7, I'm successfully using hash() to place objects into buckets stored persistently on disk. A mockup code looks like this: class PersistentDict(object): def __setitem__(self, key, value): bucket_index = (hash(key)&0xffffffff) % self.bucket_count self._store_to_bucket(bucket_index, key, value) def __getitem__(self, key): bucket_index = (hash(key)&0xffffffff) % self.bucket_count return self._fetch_from_bucket(bucket_index)[key] In python3, hash() uses a random or fixed salt, which

问题 I'm trying to learn python scraping and came across a program to scrape a set number of images from google image search results I changed it to go for 5 images, it was working for a while but it stopped working recently with showing outputs such as there are 0 images import requests import re import urllib2 import os import cookielib import json def get_soup(url,header): return BeautifulSoup(urllib2.urlopen(urllib2.Request(url,headers=header)),'html.parser') query = raw_input("query image")#

问题 I'm trying to learn python scraping and came across a program to scrape a set number of images from google image search results I changed it to go for 5 images, it was working for a while but it stopped working recently with showing outputs such as there are 0 images import requests import re import urllib2 import os import cookielib import json def get_soup(url,header): return BeautifulSoup(urllib2.urlopen(urllib2.Request(url,headers=header)),'html.parser') query = raw_input("query image")#

问题 I'm trying to learn python scraping and came across a program to scrape a set number of images from google image search results I changed it to go for 5 images, it was working for a while but it stopped working recently with showing outputs such as there are 0 images import requests import re import urllib2 import os import cookielib import json def get_soup(url,header): return BeautifulSoup(urllib2.urlopen(urllib2.Request(url,headers=header)),'html.parser') query = raw_input("query image")#

问题 I have a Python 3 file. I want to use an open-source tool on the internet (nltk), but unfortunately it only supports Python 2. There is no way for me to convert it to Python 3, nor can I convert my Python 3 file to Python 2. If the user does not give a certain argument (on argparse) then I do something in my file. If the user does give a certain argument, however, I need to use nltk. Writing a Python 2 script that uses nltk and then executing script that in my Python 3 script My current idea

问题 When copy.copy or copy.deepcopy is called on an instance of a user-defined class that does not have a __copy__ or __deepcopy__ method, what does Python guarantee will happen? The official docs are disturbingly non-explicit on this matter. Will the function always just return a new instance of the same class with a shallow/deep copy of the original object's __dict__ (or whatever the equivalent is when __slots__ are involved)? Can the behavior differ between CPython, PyPy, etc.? Does the

问题 When copy.copy or copy.deepcopy is called on an instance of a user-defined class that does not have a __copy__ or __deepcopy__ method, what does Python guarantee will happen? The official docs are disturbingly non-explicit on this matter. Will the function always just return a new instance of the same class with a shallow/deep copy of the original object's __dict__ (or whatever the equivalent is when __slots__ are involved)? Can the behavior differ between CPython, PyPy, etc.? Does the

问题 When copy.copy or copy.deepcopy is called on an instance of a user-defined class that does not have a __copy__ or __deepcopy__ method, what does Python guarantee will happen? The official docs are disturbingly non-explicit on this matter. Will the function always just return a new instance of the same class with a shallow/deep copy of the original object's __dict__ (or whatever the equivalent is when __slots__ are involved)? Can the behavior differ between CPython, PyPy, etc.? Does the

问题 When copy.copy or copy.deepcopy is called on an instance of a user-defined class that does not have a __copy__ or __deepcopy__ method, what does Python guarantee will happen? The official docs are disturbingly non-explicit on this matter. Will the function always just return a new instance of the same class with a shallow/deep copy of the original object's __dict__ (or whatever the equivalent is when __slots__ are involved)? Can the behavior differ between CPython, PyPy, etc.? Does the

问题 I have python def definition which seems working for python3: def get_default_device(use_gpu: bool = True) -> cl.Device: Under python2 I get the following syntax error: root:~/pyopencla/ch3# python map_copy.py Traceback (most recent call last): File "map_copy.py", line 9, in <module> import utility File "/home/root/pyopencla/ch3/utility.py", line 6 def get_default_device(use_gpu: bool = True) -> cl.Device: ^ SyntaxError: invalid syntax How to make type hints compatible with python2? 回答1: