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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...
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 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
...
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...
Boost程序库完全开发指南——深入C++“准”标准库高清PDF版 - 文档下载 - ...
Boost程序库完全开发指南——深入C++“准”标准库高清PDF版C++ Boost 标准库Boost是一个功能强大、构造精巧、跨平台、开源并且完全免费的C++程序库，有着C++‘准’标准库的美誉。它由C++标准委员会部分成员...Boost是一个功能...
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'...
How to beautify JSON in Python?
... here, it also includes a line using json.dumps() Using it with aiohttp on python3.7, didn't need to use the sys module and unicode(String, encoding). Basically it becomes == highlight(formatted_json, lexers.JsonLexer(), formatters.TerminalFormatter())
– DanglingPointer
...
Determine if Python is running inside virtualenv
...he following invocation:
$ python2 test.py
outside virtualenv or venv
$ python3 test.py
outside virtualenv or venv
$ python2 -m virtualenv virtualenv2
...
$ . virtualenv2/bin/activate
(virtualenv2) $ python test.py
inside virtualenv or venv
(virtualenv2) $ deactivate
$ python3 -m virtualenv v...