Script vs. Module Here’s an explanation. The short version is that there is a big difference between directly running a Python file, and importing that file from somewhere else. Just knowing what directory a file is in does not determine what package Python thinks it is in. That depends, additionally, on how you load the … Read more
Chaining comparison operators: >>> x = 5 >>> 1 < x < 10 True >>> 10 < x < 20 False >>> x < 10 < x*10 < 100 True >>> 10 > x <= 9 True >>> 5 == x > 4 True In case you’re thinking it’s doing 1 < x, which comes … Read more
One easy way would be to reassign the dataframe with a list of the columns, rearranged as needed. This is what you have now: In [6]: df Out[6]: 0 1 2 3 4 mean 0 0.445598 0.173835 0.343415 0.682252 0.582616 0.445543 1 0.881592 0.696942 0.702232 0.696724 0.373551 0.670208 2 0.662527 0.955193 0.131016 0.609548 0.804694 0.632596 … Read more
setup.py is a python file, the presence of which is an indication that the module/package you are about to install has likely been packaged and distributed with Distutils, which is the standard for distributing Python Modules. This allows you to easily install Python packages. Often it’s enough to write: $ pip install . pip will … Read more
To answer your first question… .format just seems more sophisticated in many ways. An annoying thing about % is also how it can either take a variable or a tuple. You’d think the following would always work: “Hello %s” % name yet, if name happens to be (1, 2, 3), it will throw a TypeError. … Read more
Use os.path.isdir for directories only: >>> import os >>> os.path.isdir(‘new_folder’) True Use os.path.exists for both files and directories: >>> import os >>> os.path.exists(os.path.join(os.getcwd(), ‘new_folder’, ‘file.txt’)) False Alternatively, you can use pathlib: >>> from pathlib import Path >>> Path(‘new_folder’).is_dir() True >>> (Path.cwd() / ‘new_folder”https://stackoverflow.com/”file.txt’).exists() False
Use math.isnan: >>> import math >>> x = float(‘nan’) >>> math.isnan(x) True
You need to read the Python Unicode HOWTO. This error is the very first example. Basically, stop using str to convert from unicode to encoded text / bytes. Instead, properly use .encode() to encode the string: p.agent_info = u’ ‘.join((agent_contact, agent_telno)).encode(‘utf-8’).strip() or work entirely in unicode.
Since this question was asked in 2010, there has been real simplification in how to do simple multithreading with Python with map and pool. The code below comes from an article/blog post that you should definitely check out (no affiliation) – Parallelism in one line: A Better Model for Day to Day Threading Tasks. I’ll … Read more
Use a Metaclass I would recommend Method #2, but you’re better off using a metaclass than a base class. Here is a sample implementation: class Singleton(type): _instances = {} def __call__(cls, *args, **kwargs): if cls not in cls._instances: cls._instances[cls] = super(Singleton, cls).__call__(*args, **kwargs) return cls._instances[cls] class Logger(object): __metaclass__ = Singleton Or in Python3 class Logger(metaclass=Singleton): … Read more