Polyglot CheatSheet - Operators
Last Updated: 2021-12-10
Python
Swap
a, b = b, a
TreeNode Definition
class TreeNode:
def __init__(self, val):
self.val = val
self.left, self.right = None, None
If You Forget Function Name
Use dir()
to check the function names:
>>> dir([])
[... 'append', 'clear', 'copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']
Or pretty print:
>>> import pprint; pprint.pprint(dir([]))
[ ...
'append',
'clear',
'copy',
'count',
'extend',
'index',
'insert',
'pop',
'remove',
'reverse',
'sort']
All and ANY
ALL: if every one is truthy
>>> all([1, "abc", [False]])
True
>>> all([1, 0, 1])
False
ANY: if any one is truthy
>>> any([1, 0, 0])
True
>>> any(["", 0, 0])
False
Conversions
string to char array
>>> s = "asdf"
>>> [c for c in s]
['a', 's', 'd', 'f']
int to char
>>> chr(97)
'a'
char to int
>>> ord('a')
97
int to binary
>>> format(14, 'b')
'1110'
int to hex
>>> '%#x' % 255, '%x' % 255, '%X' % 255
('0xff', 'ff', 'FF')
>>> format(255, '#x'), format(255, 'x'), format(255, 'X')
('0xff', 'ff', 'FF')
>>> f'{255:#x}', f'{255:x}', f'{255:X}'
('0xff', 'ff', 'FF')