python: int and long are unified

Since Python 2.4, int and long are unified. Furthermore, from Python 3, int is the only type for integer, which has the capacity of long in Python 2.

sys.maxint returns the maximum integer number that Python can hold.

see also

• How does Python manage int and long?

python: parse boolean from string

def parse_bool(s):
    return s.lower() in ("yes", "true", "T", "1")

NOTE:

bool('foo') # True
bool('') # False

You can not use the above function to parse boolean from string.

python: check if a variable is a integer

if isinstance(var, int):
    print("It is integer")

On python 2:

if is instance(var, (int, long)):
    print("It is integer")

python: check if a variable is a string

import sys

if isinstance(var, basestring if sys.version_info[0]<3 else str):
    print("it is string") # var is string

see also

• stackoverflow

python: conditional expression

x = true_value if condition else false_value

if isinstance(s, basestring if sys.version_info[0]<3 else str):
    print('It is a str.')

see also

• 1 PEP 308: Conditional Expressions

python: dictionary comprehension

dict = { 'a':1, 'b':2 }
dict = { k: str(dict[k]) for k in dict.keys() }
print(dict)

• http://stackoverflow.com/questions/14507591/python-dictionary-comprehension

main function in python module

class A:
    def __init__(self):
        pass


def main():
    print("Hello World")


if __name__ == '__main__':
    main()

see also

• stackoverflow

Google coding style guide for Python

Google code style for python.