Ben Chuanlong Du's Blog

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Static Type Checking of Python Scripts Using pytype

Configuration

There are 3 ways to control the behavior of `pytype.

  1. Pass command-line options to pytype.

  2. Specify a configuration file using pytype --config /path/to/config/file .... You can generate an example configuration file using the command pytype --generate-config pytype.cfg.

  3. If no configuration file is found, pytype uses the …

Call Java Using PyJNIus from Python

PyJNIus is a simple-to-use Java interface for Python. However, JPype is a better alternative.

Installation

pip install Cython
pip install pyjnius

Example with Imported Jar

import os
os.environ["CLASSPATH"] = "/path/to/your.jar"
from jnius import autoclass
YourClass = autoclass(path.to.YourClass)
yourObj = YourClass()

Note: Avoid using the same …

Java Interfaces for Python

JPype, py4j and PyJNIus are all good options for Java interface for Python. Jpype is easy to use and widely adopted. PyJNIus is an even easier solution compred to JPype. py4j is more complicated to use compared to JPype and PyJNIus, however, it has a better performance, generally speaking.

JPype …

Avoid Database Lock in SQLite3

  1. According to https://www.sqlite.org/lockingv3.html, POSIX advisory locking is known to be buggy or even unimplemented on many NFS implementations (including recent versions of Mac OS X) and that there are reports of locking problems for network filesystems under Windows. So, the rule of thumb is to …

Work with Long Strings in Python

This article discusses different ways to write long strings in Python.

Long String in One Line

A long string can be put on the the same line, which is ugly of course.

The eval Function in Python

The function eval takes a single line of code as string, evaluates it, and returns the value. Notice that objects in the evaluated expression must be present in the current scope, otherwise, exceptions will be thrown.

Even though eval (together with exec) might be useful in some situations, e.g., when implementing a REPL. It is strongly suggested that you avoid using eval