Python/CheatSheet: Difference between revisions

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= Files =
= Files =
<blockquote>
<pre>
open (ordersfile, 'rb') as file
</pre>
</blockquote>
<blockquote>
<pre>
with open (ordersfile, 'rb') as fp:
    orders = pickle.load(fp)
</pre>
</blockquote>


= Escape sequences =
= Escape sequences =

Revision as of 18:29, 20 October 2017

Variables

Tuples

  • not changeable
a = (1,2,3)
b = ("test", "with", "strings")
b[0]
-> test

Lists

  • changeable
c = [4,5,6]
d = ["this", "is", "a", "list"]
d[0]
-> this
d[0] = 'new'
d[0:1] = ['new', 'stuff']
d.append('dude')
d.count('new')
del d[0:1]
d.extend(['more', 'elements']
d.index(x)
d.insert(i,x)
d.pop()
d.remove(x)
d.reverse()
d.sort()

Dictionaries

  • mapping
e = {'size':5, 'color':'red', 'weight':100}
e['size']
-> 5

Operators

+
-
*
/
//
%
**

&
|

<
<=
>
>=
!=
==
is
is not
in
not in
and
or

Flow Control

If Then Else

if x < 0:
    print('Negative')
elif x == 0:
    print('Zero')
else:
    print('More')


For loops

for x in ['cat', 'dog', 'bird']:
    print (x)

for i in [1,2,3,4,5]:
    print (i+10)

While loops

while test:
    print (answer)


while True:
    print (answer)
    if answer == '2':
        break
x = 0
while x < 50:
    x = x+1    

try ... except

try:
    result = x / y
except ZeroDivisionError:
     print("division by zero!")
else:
     print("result is", result)
finally:
     print("executing finally clause")

Statements

assert
break
continue
del
exec
global
import
nonlocal
pass
raise
return
yield

Strings

string = "Hello World"
string = 'Hello World'

string[4]                             # = 'o'
string.split(' ')                     # ['Hello', 'World']

String functions

capitalize()
center(width)
count(sub,start,end)
decode()
encode()
endswith(sub)
expandtabs()
find(sub,start,end)
index(sub,start,end)
isalnum()
isalpha()
isdigit()
islower()
isspace()
istitle()
isupper()
join()
ljust(width)
lower()
lstrip()
partition(sep)
replace(old,new)
rfind(sub,start,end)
rindex(sub,start,end)
rjust(width)
rpartition(sep)
rsplit(sep)
rstrip()
split(sep)
splitlines()
startswith(sub)
strip()
swapcase()
title()
translate(table)
upper()
zfill(width)

Functions

datetime

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

time

replace()
utcoffset()
isoformat()
__str__()
dst()
tzname()
strftime(format)

strftime & strptime format






Input & Output

x = input("input:")
print(x+12)
print("Hello world")
print("Integer: %i, Float: %6.2f" % (123, 12.043))
print("Integer: {intvar:i}, Float: {floatvar:.2f}")
print("value of x: {0:05d}".format(x))

Files

open (ordersfile, 'rb') as file
with open (ordersfile, 'rb') as fp:
    orders = pickle.load(fp)

Escape sequences

ES Note
\\ backslash
\' '
\" "
\b backspace
\f form feed
\n line feed
\t horizontal tab
\v vertical tab
\N{Name} Unicode by name
\uxxxx 16bit unicode
\uxxxxxxxx 32bit unicode
\123 ASCII code
\xhh Extended ASCII code (hex)