Polkadot JAM Slides - Token2049 - By Dr. Gavin Wood
Python Cheat Sheet
1. Enabling Your Growth Through
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Python Cheat Sheet
Python sys Variables Python List Methods
argv Command line args append(item) pop(position)
builtin_module_names Linekd C modules count(item) remove(item)
byteorder Native byte order extend(list) reverse()
check_interval Signal check frequency index(item) sort()
exec_prefix Root directory insert(position, item)
executable Name of executable
exitfunc Exit function name Python String Methods
modules Loaded modules capitalize() * lstrip()
path Search path center(width) partition(sep)
platform Current platform count(sub, start, end) replace(old, new)
stdin, stdout, stderr File objects for I/O decode() rfind(sub, start ,end)
version_info Python version info encode() rindex(sub, start, end)
winver Version number endswith(sub) rjust(width)
expandtabs() rpartition(sep)
Python sys.argv find(sub, start, end) rsplit(sep)
sys.argv[0] foo.py index(sub, start, end) rstrip()
sys.argv[1] bar isalnum() * split(sep)
sys.argv[2] -c isalpha() * splitlines()
sys.argv[3] qux isdigit() * startswith(sub)
sys.argv[4] --h islower() * strip()
sys.argv for the command: isspace() * swapcase() *
$ python foo.py bar -c qux --h istitle() * title() *
isupper() * translate(table)
Python os Variables join() upper() *
altsep Alternative sep ljust(width) zfill(width)
curdir Current dir string lower() *
defpath Default search path Methods marked * are locale dependant for
devnull Path of null device 8-bit strings.
extsep Extension separator
linesep Line separator Python File Methods
name Name of OS close() readlines(size)
pardir Parent dir string flush() seek(offset)
pathsep Patch separator fileno() tell()
sep Path separator isatty() truncate(size)
Registered OS names: "posix", "nt", next() write(string)
"mac", "os2", "ce", "java", "riscos" read(size) writelines(list)
readline(size)
2. Enabling Your Growth Through
www.GlowTouch.com Application Development & Support Services
Python Cheat Sheet
Python Class Special Methods Python Date Formatting
__new__(cls) __lt__(self, other) %a Abbreviated weekday (Sun)
__init__(self, args) __le__(self, other) %A Weekday (Sunday)
__del__(self) __gt__(self, other) %b Abbreviated month name (Jan)
__repr__(self) __ge__(self, other) %B Month name (January)
__str__(self) __eq__(self, other) %c Date and time
__cmp__(self, other) __ne__(self, other) %d Day (leading zeros) (01 to 31)
__index__(self) __nonzero__(self) %H 24 hour (leading zeros) (00 to 23)
__hash__(self) %I 12 hour (leading zeros) (01 to 12)
__getattr__(self, name) %j Day of year (001 to 366)
__getattribute__(self, name) %m Month (01 to 12)
__setattr__(self, name, attr) %M Minute (00 to 59)
__delattr__(self, name) %p AM or PM
__call__(self, args, kwargs) %S Second (00 to 61⁴)
%U Week number¹ (00 to 53)
Python Indexes and Slices %w Weekday² (0 to 6)
len(a) 6 %W Week number³ (00 to 53)
a[0] 0 %x Date
a[5] 5 %X Time
a[-1] 5 %y Year without century (00 to 99)
a[-2] 4 %Y Year (2008)
a[1:] [1,2,3,4,5] %Z Time zone (GMT)
a[:5] [0,1,2,3,4] %% A literal "%" character (%)
a[:-2] [0,1,2,3] ¹ Sunday as start of week. All days in a new
a[1:3] [1,2] year preceding the first Sunday are
a[1:-1] [1,2,3,4] considered to be in week 0.
b=a[:] Shallow copy of a ² 0 is Sunday, 6 is Saturday.
Indexes and Slices of a=[0,1,2,3,4,5] ³ Monday as start of week. All days in a new
year preceding the first Monday are
Python Datetime Methods considered to be in week 0.
today() fromordinal(ordinal) ⁴ This is not a mistake. Range takes account
now(timezoneinfo) combine(date, time) of leap and double-leap seconds.
utcnow() strptime(date, format)
fromtimestamp(timestamp)
utcfromtimestamp(timestamp)
Python Time Methods
replace() utcoffset()
isoformat() dst()
__str__() tzname()
strftime(format)