tkinter thread

https://stackoverflow.com/questions/459083/how-do-you-run-your-own-code-alongside-tkinters-event-loop

Photo image error in thread (because belongs to process

splsh_img = tkinter.PhotoImage(file=file,master=wlcm_scrn)

def clear_all_cache():

pylint: disable = protected-access

import functools
import gc

gc.collect()
wrappers = [
    a for a in gc.get_objects()
    if isinstance(a, functools._lru_cache_wrapper)]

for wrapper in wrappers:
    wrapper.cache_clear()

Decorator


# Used in vimspector to check if object._connected 
def IfConnected( fct ):
  """Decorator, call fct if self._connected else echo warning
  The decorated member function must belong to an object with _connection
  """
  def wrapper(*args, **kwargs):
    if not args[0]._connection:
      MessageNoConnection( )
      return
    return fct(*args, **kwargs)
  return wrapper


# Instead of passing in the instance attribute at class definition time, check it at runtime:
def check_authorization(f):
    def wrapper(*args):
        print args[0].url
        return f(*args)
    return wrapper

class Client(object):
    def __init__(self, url):
        self.url = url

    @check_authorization
    def get(self):
        print 'get'

>>> Client('http://www.google.com').get()
http://www.google.com
get

# Arguments without
@decorator
def foo(*args, **kwargs):
    pass

# -> 
foo = decorator(foo)

# Arugments with
@decorator_with_args(arg)
def foo(*args, **kwargs):
    pass

# ->
foo = decorator_with_args(arg)(foo)
def memoize(function):
  memo = {}
  def wrapper(*args):
    if args in memo:
      return memo[args]
    else:
      rv = function(*args)
      memo[args] = rv
      return rv
  return wrapper

# Example
@memoize
def fibonacci(n):
  if n < 2: return n
  return fibonacci(n - 1) + fibonacci(n - 2)

# Class memoization
class memorize(dict):
  def __init__(self, func):
      self.func = func

  def __call__(self, *args):
      return self[args]

  def __missing__(self, key):
      result = self[key] = self.func(*key)
      return result

Inspect

def info(msg):
    frm = inspect.stack()[1]
    mod = inspect.getmodule(frm[0])
    print('[%s] %s' % (mod.__name__, msg))

Int

def cmp(a, b):
    return (a > b) - (a < b)

String

List

a = ["foo", "melon"]
b = [True, False]
c = list(itertools.product(a, b))
>> [("foo", True), ("foo", False), ("melon", True), ("melon", False)]
list(itertools.combinations([1, 2, 3, 4, 5], 2))

Dict

example_dict.get(‘key1’, {}).get(‘key2’)

Function, Utils

Why love Python ?

============================================================================== STATEMENTS c-python-statement

If-Statement ~ if expression: statements elif expression: statements else: statements

While-Loop ~ while expression: statements

For-Loop ~ for var in collection: statements

Counting-For-Loop ~ for i in range(start, end [, step]): statements -> (start is included; end is not)

with context_manager_classs as cr ~ a Context Manager class must have __enter__ and __exit__ methods

FUNCTION DEFINITIONS c-python-function def name(arg1, arg2, …): statements return expr ret = name(arg1, arg2)

EXCEPTION c-python-exception try: statements except [exception type [as var]]: statements finally: statements

============================================================================== TYPES c-python-types

Integer -256, 15 Float 253.23, 1.253e-10 String “Hello”, ‘Goodbye’, ""“Multiline”"" Boolean True, False List [ value, … ] Tuple ( value, … )
-> Parentheses usually optional Dictionary { key: value, … } Set { value:, value, … } -> Create an empty set with set()

============================================================================== OPERATORS c-python-operators

Arithmetic Operators ~ x + y Add x - y Subtract x * y Multiply x / y Divide x % y Modulus x ** y Exponent Assignment shortcuts: x op= y Example: x += 1 increments x

Comparison Operators ~ x < y Less x <= y Less or eq x > y Greater x >= y Greater or eq x == y Equal x != y Not equal

Boolean Operators ~ not x
x and y x or y

============================================================================== MISC c-python-misc

Conversion Functions ~ int(expr) Converts expr to integer float(expr) Converts expr to float str(expr) Converts expr to string chr(num) ASCII char num

String / List / Tuple Operations ~ len(s) Length of s s[i] Ith item in s (0-based) s[start : end] Slice of s from start (included) to end (excluded) x in s true if x is contained in s x not in s true if x is not contained in s s + t The concatenation of s with t s * n n copies of s concatenated sorted(s) A sorted copy of s s.index(item) Position in s of item

More String Operations ~ s.lower() Lowercase copy of s s.replace(old, new) Copy of s with old replaced with new s.split( delim ) List of substrings delimited by delim s.strip() Copy of s with whitespace trimmed s.upper() Uppercase copy of s -> See also http://docs.python.org/library/stdtypes.html
#string-methgds

Mutating List Operations ~ del lst[i] Deletes ith item from lst lst.append(e) Appends e to lst lst.insert(i, e) Inserts e before ith item in lst lst.sort() Sorts lst -> See also http://docs.python.org/library/stdtypes.html
#typesseq-mutable

Dictionary Operations ~ len(d) Number of items in d del d[key] Removes key from d key in d True if d contains key d.keys() Returns a list of keys in d -> See also http://docs.python.org/library/stdtypes.html
#mapping-types-dict

Environment ~ sys.argv List of command line arguments (argv[0] is executable) os.environ Dictionary of environment variables os.curdir String with path of current directory -> import sys; print(sys.argv) -> or -> from sys import argv; print(argv)}

String Formatting ~ “Hello, {0} {1}”.format(“abe”, “jones”) -> Hello, abe jones “Hello, {fn} {ln}”.format(fn=“abe”, ln=“jones”) -> Hello, abe jones “You owe me ${0:,.2f}”.format(253422.3) -> You owe me $253,422.30 now = datetime.now() ‘{:%Y-%m-%d %H:%M:%S}’.format(now) -> 2012-05-16 15:04:33 -> See http://docs.python.org/library/string.html
#format-specification-mini-language

Useful Functions ~ exit( num ) Terminate program with exit num raw_input(“prompt”) Print prompt and readline() from stdin -> Use input(“prompt”) in Python 3

============================================================================== SYS c-python-sys

Python sys Variables ~ argv Command line args builtin_module_names Linked C modules byteorder Native byte order check_interval Signal check frequency exec_prefix Root directory executable Name of executable exitfunc Exit function name modules Loaded modules path Search path platform Current platform stdin, stdout, stderr File objects for I/O version_info Python version info winver Version number

Python sys.argv ~ -> sys.argv for the command: -> python foo.py bar -c qux –h sys.argv[0] foo.py sys.argv[1] bar sys.argv[2] -c sys.argv[3] qux sys.argv[4] –h

============================================================================== OS c-python-os

altsep Alternative sep curdir Current dir string defpath Default search path devnull Path of null device extsep Extension separator linesep Line separator name Name of OS pardir Parent dir string pathsep Patch separator sep Path separator -> Registered OS names: “posix”, “nt”, “mac”, “os2”, “ce”, “java”, “riscos”

============================================================================== CLASS c-python-class

Python Class Special Methods ~ new(cls) init(self, args) del(self) repr(self) str(self) cmp(self, other) index(self) hash(self) getattr(self, name) getattribute(self}, name) setattr(self, name, attr) delattr(self, name) call(self, args, kwargs) lt(self, other) le(self, other) gt(self, other) ge(self, other) eq(self, other) ne(self, other) nonzero(self)

Python List Methods ~ append(item) count(item) extend(list) index(item) insert(position, item) remove(item) pop(position) reverse() sort()

Python String Methods ~ capitalize() * lstrip() center(width) partition(sep) count(sub, start, end) replace(old, new) decode() rfind(sub, start ,end) encode() rindex(sub, start, end) endswith(sub) rjust(width) expandtabs() rpartition(sep) find(sub, start, end) rsplit(sep) index(sub, start, end) rstrip() isalnum() * split(sep) isalpha() * splitlines() isdigit() * startswith(sub) islower() * strip() isspace() * swapcase() istitle() title() isupper() translate(table) join() upper() ljust(width) zfill(width) lower() -> Methods marked * are locale dependant for 8-bit strings.

Python File Methods ~ close() readlines(size) flush() seek(offset) fileno() tell() isatty() truncate(size) next() write(string) read(size) writelines(list) readline(size)

Python Indexes and Slices ~ -> Indexes and Slices of a=[0,1,2,3,4,5] len(a) = 6 a[0] = 0 a[5] = 5 a[-1] = 5 a[-2] = 4 a[1:] = [1,2,3,4,5] a[:5] = [0,1,2,3,4] a[:-2] = [0,1,2,3] a[1:3] = [1,2] a[1:-1] = [1,2,3,4] b=a[:] = Shallow copy of a

============================================================================== DATE c-python-date

Python Datetime Methods ~ today() fromordinal(ordinal) now(timezoneinfo) combine(date, time) utcnow() strptime(date, format) fromtimestamp(timestamp) utcfromtimestamp(timestamp)

Python Time Methods ~ replace() utcoffset() isoformat() dst() str() tzname() strftime(format)

Python Date Formatting ~ %a Abbreviated weekday (Sun) %A Weekday (Sunday) %b Abbreviated month name (Jan) %B Month name (January) %c Date and time %d Day (leading zeros) (01 to 31) %H 24 hour (leading zeros) (00 to 23) %I 12 hour (leading zeros) (01 to 12) %j Day of year (001 to 366) %m Month (01 to 12) %M Minute (00 to 59) %p AM or PM %S Second {4} %U Week number {1} (00 to 53) %w Weekday {2} (0 to 6) %W Week number {3} (00 to 53) %x Date %X Time %y Year without century (00 to 99) %Y Year (2008) %Z Time zone (GMT) %% A literal “%” character (%) -> 1. Sunday as start of week. All days in a new year preceding the first Sunday are considered to be in week 0. -> 2. 0 is Sunday, 6 is Saturday. -> 3. Monday as start of week. All days in a new year preceding the first Monday are considered to be in week 0. -> 4. This is not a mistake. Range takes account of leap and double-leap seconds.}


# Loop-Over-Sequence
for index, value in enumerate(seq):
  print("{} : {}".format(index, value))


# Loop-Over-Dictionary
for key in sorted(dict):
  print(dict[key])


# Read-a-File
with open("filename", "r") as f:
  for line in f:
    line = line.rstrip("\textbackslash{}n")
# Strip newline
    print(line)
<python


# Entropy
s = [ord(a) for a in "azerty"] ;\
h = np.histogram(s, bins=range(256))[0] ;\
print(   scipy.stats.entropy(h) / np.log(len(set(s)))   )

vim: ft=myhelp