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Are tuples more efficient than lists in Python?
...gives tuples a small speed advantage for indexed lookups and unpacking:
$ python3.6 -m timeit -s 'a = (10, 20, 30)' 'a[1]'
10000000 loops, best of 3: 0.0304 usec per loop
$ python3.6 -m timeit -s 'a = [10, 20, 30]' 'a[1]'
10000000 loops, best of 3: 0.0309 usec per loop
$ python3.6 -m timeit -s 'a ...
How to install psycopg2 with “pip” on Python?
... package from source:
Debian/Ubuntu
Python 3
sudo apt install libpq-dev python3-dev
You might need to install python3.8-dev or similar for e.g. Python 3.8.
Python 21
sudo apt install libpq-dev python-dev
If that's not enough, try
sudo apt install build-essential
or
sudo apt install post...
How to import other Python files?
...
Is it still accurate in 2019? Is it python3 or 2?
– Sandburg
Jan 24 '19 at 11:34
|
show 2 more commen...
How to avoid “RuntimeError: dictionary changed size during iteration” error?
...
your python3 solution is not work when you want to delete an object in inner dict. for example you have a dic A and dict B in dict A. if you want to delete object in dict B it occurs error
– Ali-T
...
C++并发编程（中文版） - 文档下载 - 清泛网 - 专注C/C++及内核技术
C++并发编程（中文版）C++并发编程（中文版）作为对《C++ Concurrency in Action》的中文翻译。本书是基于C++11新标准的并发和多线程编程深度指南。从std::thr 作为对《C++ Concurrency in Action》的中文翻译。
本书是基于C++11新标准的并...
为AppInventor2开发自己的拓展(Extension) - App Inventor 2 拓展 - 清泛IT社区，为创新赋能！
...cmd 命令行输入ant命令出现以上结果证明配置成功。
源码下载https://github.com/mit-cml/appinventor-sources国内下载非常非常缓慢，这个项目比较大，也许2天都下载不完，不过没关系，我们早已提供已下载好的工程源码，关注页面顶部公...
How do I update pip itself from inside my virtual environment?
...https://bootstrap.pypa.io/get-pip.py -O ./get-pip.py
python ./get-pip.py
python3 ./get-pip.py
This will install the current version which at the time of writing this solution is 9.0.1 which is way beyond what Debian provides.
$ pip --version
pip 9.0.1 from /home/myhomedir/myvirtualenvdir/lib/...
How to run code when a class is subclassed? [duplicate]
...s:
__metaclass__ = Watcher
where Watcher is a subclass of type.
In Python3 the syntax has been changed to
class SuperClass(metaclass=Watcher)
Both are equivalent to
Superclass = Watcher(name, bases, clsdict)
where in this case, name equals the string 'Superclass', and bases is the tupl...
Setting Django up to use MySQL
...
If you are using python3.x then Run below command
pip install mysqlclient
Then change setting.py like
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.mysql',
'NAME': 'DB',
'USER': 'username',
'PASSWORD': 'passwd'...
LR性能测试结果样例分析 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...。使用网页细分图，可以分析网站上有问题的元素（例如下载很慢的图像或打不开的链接）。
我们这里查看一下网页细分图中的“Page Download Time Breakdown”，点击错误！未找到引用源。左边的“New Graph”，出现图1- 14，展开“Web ...