Python Basics (2023-11-29 - 2023-12-01)

blah blah

print('hello world')

hello world

a = 42

if a == 42:
    print('the answer')

the answer

BlahBlah

del a

a = 42

print(a)

42

a

42

type(a)

int

print(type(a))

<class 'int'>

i = 100

hex(i)

'0x64'

bin(i)

'0b1100100'

i = 300

bin(i)

'0b100101100'

i = 1

bin(i)

'0b1'

bin(0)

'0b0'

i = 2**64 - 1

bin(i)

'0b1111111111111111111111111111111111111111111111111111111111111111'

len(bin(i))

66

i += 1

i

18446744073709551616

len(bin(i))

67

2**10000

19950631168807583848837421626835850838234968318861924548520089498529438830221946631919961684036194597899331129423209124271556491349413781117593785932096323957855730046793794526765246551266059895520550086918193311542508608460618104685509074866089624888090489894838009253941633257850621568309473902556912388065225096643874441046759871626985453222868538161694315775629640762836880760732228535091641476183956381458969463899410840960536267821064621427333394036525565649530603142680234969400335934316651459297773279665775606172582031407994198179607378245683762280037302885487251900834464581454650557929601414833921615734588139257095379769119277800826957735674444123062018757836325502728323789270710373802866393031428133241401624195671690574061419654342324638801248856147305207431992259611796250130992860241708340807605932320161268492288496255841312844061536738951487114256315111089745514203313820202931640957596464756010405845841566072044962867016515061920631004186422275908670900574606417856951911456055068251250406007519842261898059237118054444788072906395242548339221982707404473162376760846613033778706039803413197133493654622700563169937455508241780972810983291314403571877524768509857276937926433221599399876886660808368837838027643282775172273657572744784112294389733810861607423253291974813120197604178281965697475898164531258434135959862784130128185406283476649088690521047580882615823961985770122407044330583075869039319604603404973156583208672105913300903752823415539745394397715257455290510212310947321610753474825740775273986348298498340756937955646638621874569499279016572103701364433135817214311791398222983845847334440270964182851005072927748364550578634501100852987812389473928699540834346158807043959118985815145779177143619698728131459483783202081474982171858011389071228250905826817436220577475921417653715687725614904582904992461028630081535583308130101987675856234343538955409175623400844887526162643568648833519463720377293240094456246923254350400678027273837755376406726898636241037491410966718557050759098100246789880178271925953381282421954028302759408448955014676668389697996886241636313376393903373455801407636741877711055384225739499110186468219696581651485130494222369947714763069155468217682876200362777257723781365331611196811280792669481887201298643660768551639860534602297871557517947385246369446923087894265948217008051120322365496288169035739121368338393591756418733850510970271613915439590991598154654417336311656936031122249937969999226781732358023111862644575299135758175008199839236284615249881088960232244362173771618086357015468484058622329792853875623486556440536962622018963571028812361567512543338303270029097668650568557157505516727518899194129711337690149916181315171544007728650573189557450920330185304847113818315407324053319038462084036421763703911550639789000742853672196280903477974533320468368795868580237952218629120080742819551317948157624448298518461509704888027274721574688131594750409732115080498190455803416826949787141316063210686391511681774304792596709376

type(i)

int

type_of_i = type(i)

print(type_of_i)

<class 'int'>

msg = 'hello world'
print(msg)

hello world

type(msg)

str

type(print)

builtin_function_or_method

type(i)

int

i = ['abc', 1, 666.42]

type(i)

list

Syntax

answer = 666

if answer == 42:
    print('yay')
    print('das ist mal eine antwort')
else:
    print('schade')

schade

if answer == 42:
    print('yay')
print('das ist mal eine antwort')

das ist mal eine antwort

Variables

msg = 'hello world'

print(msg)

hello world

print(msg*2)

hello worldhello world

i = 0
while i < 7:
    print(i)
    i += 1

0
1
2
3
4
5
6

a = 42

type(a)

int

a = 1.5

type(a)

float

a = [42, 'blah']

type(a)

list

a = 42

b = a

a

42

b

42

id(a)

140572055569936

id(b)

140572055569936

a = 7

a

7

b

42

c = b

b += 1

b

43

c

42

l1 = [1, 'two']

l2 = l1

id(l1) == id(l2)

True

l1 is l2

True

l1.append(3.0)

l1

[1, 'two', 3.0]

l2

[1, 'two', 3.0]

l3 = [1, 'two']

l1 == l3

False

l1 is l3

False

DataTypes

What is Equality? (==)

a = '666'

b = 666

a == b

False

int(a) == b

True

Integers

3/2

1.5

3//2

1

import math

math.sqrt(4)

2.0

round(4.500001)

5

help(round)

Help on built-in function round in module builtins:

round(number, ndigits=None)
    Round a number to a given precision in decimal digits.

    The return value is an integer if ndigits is omitted or None.  Otherwise
    the return value has the same type as the number.  ndigits may be negative.

round(4.65, 0)

5.0

6/3 == 100/50

True

if abs(6/3 - 100/50) < 0.001:
    print('eh gleich')

eh gleich

round(3.499999999999999999999999)

4

round(4.4999)

4

def my_round(f):
    import math
    cf = math.ceil(f)
    diff_to_next = cf - f
    if diff_to_next <0.5001:
        return cf
    else:
        return math.floor(f)

my_round(3.5)

4

my_round(3.1)

3

my_round(3.6)

4

my_round(3.500000001)

4

Datatype Conversions

str_i = "666"

type(str_i)

str

int_i = int(str_i)

type(int_i)

int

int_i == str_i

False

str(int_i)

'666'

float_i = float(int_i)

float_i

666.0

float('666')

666.0

try:
    float('abc')
except Exception as e:
    print(type(e), e)

<class 'ValueError'> could not convert string to float: 'abc'

try:
    int('666.42')
except Exception as e:
    print(type(e), e)

<class 'ValueError'> invalid literal for int() with base 10: '666.42'

try:
    int('abc')
except Exception as e:
    print(type(e), e)

<class 'ValueError'> invalid literal for int() with base 10: 'abc'

int('abc', 16)

2748

bool(666)

True

bool(0)

False

bool('666')

True

i = 666
if i:
    print('eh')

eh

i = 0
if not i:
    print('nix')

nix

List (mutable)

l = [1, 'two', 3.0]

type(l)

list

l.append(4)

l

[1, 'two', 3.0, 4]

nocheineliste = [5, 6, 7]

l += nocheineliste

l

[1, 'two', 3.0, 4, 5, 6, 7]

l.extend([8, 9, 10])
l

[1, 'two', 3.0, 4, 5, 6, 7, 8, 9, 10]

l[3]

4

l.append([11, 12, 13])

l

[1, 'two', 3.0, 4, 5, 6, 7, 8, 9, 10, [11, 12, 13]]

len(l)

11

666 in l

False

12 in l

False

12 == [11, 12, 13]

False

12 in l[-1]

True

Tuple (immutable)

t = (1, 'two', 3.0)
id(t)

140571746172800

type(t)

tuple

try:
    t.append(4)
except Exception as e:
    print(type(e), e)

<class 'AttributeError'> 'tuple' object has no attribute 'append'

t += (4, 5, 6)

id(t)

140571753417312

t[3]

4

t = (666)

type(t)

int

2*3+4

10

2*(3+4)

14

t = (666,)

type(t)

tuple

Dictionary (mutable)

d = {
    'one': 1,
    'two': 2,
}

d['one']

1

'one' in d

True

try:
    d['three']
except Exception as e:
    print(type(e), e)

<class 'KeyError'> 'three'

d['three'] = 3

d['three']

3

v = d.get('four')

print(v)

None

d.get('three')

3

del d['three']

'three' in d

False

Set (mutable)

s = {1, 2, 3}

3 in s

True

4 not in s

True

s.add(4)

s

{1, 2, 3, 4}

s.add(4)

s

{1, 2, 3, 4}

s.remove(1)

1 in s

False

s1 = {1, 2, 3, 4}
s2 = {3, 4, 5, 6}

s1 | s2

{1, 2, 3, 4, 5, 6}

s1 & s2

{3, 4}

s1 ^ s2

{1, 2, 5, 6}

i = 42
i.__hash__()

42

my_s = 'abc'
my_s.__hash__()

-2282548071841868421

s.add('abc')

s

{2, 3, 4, 'abc'}

try:
    s.add([1, 2, 3])
except Exception as e:
    print(type(e), e)

<class 'TypeError'> unhashable type: 'list'

s.add((1,2,3))

Boolean (immutable)

1 < 2

True

2 < 1

False

i = 0
while i < 7:
    print(i)
    i += 1

0
1
2
3
4
5
6

bool(42)

True

bool(0)

False

bool('')

False

bool('0')

True

bool(None)

False

a = 42

if a == 42:
    print('yay')
else:
    print('oioi')

yay

True and False

False

True or False

True

False or True

True

True or False and print('boah')

True

while Loops

i = 0
while i < 7:
    print(i)
    i += 1

print('ueberbleibsel', i)

0
1
2
3
4
5
6
ueberbleibsel 7

my_sum = 0
i = 0
while i < 101:
    my_sum += i
    i += 1
print(my_sum)

5050

sum(range(101))    # pythonic

5050

import random

n_tries = 5
while n_tries != 0:
    n_tries -= 1
    eyes = random.randrange(1, 7)
    if eyes == 6:
        print('win')
        break
else:
    print('lose')

win

for Loops

i = 0
while i < 5:
    print(i)
    i += 1

0
1
2
3
4

for i in range(0, 5):
    print(i)

0
1
2
3
4

for i in range(0, 5, 2):
    print(i)

0
2
4

for i in range(2, 10):
    print(i)

2
3
4
5
6
7
8
9

l = [0, 1, 2, 3, 4]
for i in l:
    print(i)

0
1
2
3
4

s = {0, 1, 2, 3, 4}
for i in s:
    print(i)

0
1
2
3
4

d = {'one': 1, 'two': 2}
for elem in d:
    print(elem)

one
two

d = {'one': 1, 'two': 2}
for elem in d.keys():
    print(elem)

one
two

for elem in d.values():
    print(elem)

1
2

for elem in d.items():
    print(elem)

('one', 1)
('two', 2)

Tuple Unpacking

for elem in d.items():
    k = elem[0]
    v = elem[1]
    print('key:', k, 'value:', v)

key: one value: 1
key: two value: 2

for k, v in d.items():
    print('key:', k, 'value:', v)

key: one value: 1
key: two value: 2

l = ['one', 2, 3.0]

a, b, c = l

print(a, b, c)

one 2 3.0

a = 1
b = 2

Exchange values of a and b!

tmp = a
a = b
b = tmp

print(a, b)

2 1

a = 1
b = 2

a, b = b, a

print(a, b)

2 1

def f():
    return 42, 666

answer, doom = f()

answer, doom

(42, 666)

Iterator Protocol

r = range(3)
type(r)

range

l = [0, 1, 2]
type(l)

list

for elem in l:
    print(elem)

0
1
2

for elem in r:
    print(elem)

0
1
2

l

[0, 1, 2]

it = iter(l)
type(it)

list_iterator

next(it)

0

next(it)

1

next(it)

2

try:
    next(it)
except Exception as e:
    print(type(e), e)

<class 'StopIteration'>

for elem in l:
    print(elem)

0
1
2

r = range(3)
type(r)

range

it = iter(r)

next(it)

0

next(it)

1

next(it)

2

try:
    next(it)
except Exception as e:
    print(type(e), e)

<class 'StopIteration'>

def my_range(stop):
    print('start')
    run = 0
    while run < stop:
        print('before yield', run)
        yield run
        print('after yield', run)
        run += 1
    print('stop iteration')

r = my_range(3)

r

<generator object my_range at 0x7f48e8543060>

it = iter(r)

next(it)

start
before yield 0

0

next(it)

after yield 0
before yield 1

1

next(it)

after yield 1
before yield 2

2

try:
    next(it)
except Exception as e:
    print(type(e), e)

<class 'StopIteration'>

def wurscht():
    yield 0
    yield 'doedel'
    yield 666.42

for elem in wurscht():
    print(elem)

0
doedel
666.42

Functions

def is_even(n):
    if n % 2 == 0:
        return True
    else:
        return False

is_even(100)

True

is_even(99)

False

Sequential Datatypes

s = 'abc'

for c in s:
    print(c)

a
b
c

s[0]

'a'

s[2]

'c'

s[1]

'b'

More About Strings

s = 'blah'

s

'blah'

'blah'

'blah'

'doesn\'t'

"doesn't"

"doesn't"

"doesn't"

"sdhcbdhcb'kjsdskbh\"akjsdhvksb"

'sdhcbdhcb\'kjsdskbh"akjsdhvksb'

s = "abc\ndef"
print(s)

abc
def

path = 'C:\some\name'

print(path)

C:\some
ame

path = 'C:\some\\name'

print(path)

C:\some\name

path = r'C:\some\name'

print(path)

C:\some\name

Regular Expressions

Potschert …

line = "     blah   .  1234   \n"

item1, item2 = line.split('.')

item1, item2

('     blah   ', '  1234   \n')

item1 = item1.strip()
item1

'blah'

int(item2.strip())

1234

Gscheit …

import re

line = "     blah   .  1234   \n"

line_re = re.compile(r"^\s*(\S+)\s*\.\s*(\d+)\s*$")

match = line_re.search(line)

type(match)

re.Match

match.group(1)

'blah'

match.group(2)

'1234'

Multiline Strings

def foo(bar):
    '''This complex function foos a bar by
    concatenating bar to itself a thousand times'''
    return bar*5

foo('abc')

'abcabcabcabcabc'

help(foo)

Help on function foo in module __main__:

foo(bar)
    This complex function foos a bar by
    concatenating bar to itself a thousand times

foo.__doc__

'This complex function foos a bar by\n    concatenating bar to itself a thousand times'

f-Strings

a = 1

f'blah {a} blah'

'blah 1 blah'

'%d %s' % (666, 'blah')

'666 blah'

'{0} {1}'.format(666, 'blah')

'666 blah'

i = 666
blah = 'blah'
f'{i} {blah}'

'666 blah'

f'{665+1} {"bla"+"h"}'

'666 blah'

Miscellaneous String Methods

'  \n\t   '.isspace()

True

'abc'.isalpha()

True

s = 'mississippi'

s.count('ss')

2

import os
os.listdir('.')

['.ipynb_checkpoints',
 'notebook-wrapper.rst',
 'notebook.ipynb',
 'agenda.rst.~1~',
 'index.rst.~1~',
 'index.rst',
 'agenda.rst.~2~',
 'agenda.rst']

filename = 'data.csv'

filename.endswith('.csv')

True

s = 'mississippi'

s.count('ss')

2

s.find('ss')

2

pos = s.find('ss')

pos

2

s.find('ss', pos + 1)

5

s.find('xx')

-1

s.index('ss')

2

try:
    s.index('xx')
except Exception as e:
    print(type(e), e)

<class 'ValueError'> substring not found

split() and join()

line = 'one:two:three'

line.split(':')

['one', 'two', 'three']

a, b, c = line.split(':')

a, b, c

('one', 'two', 'three')

items = ['one', 'two', 'three']

':'.join(items)

'one:two:three'

line

'one:two:three'

line.split(':', 1)

['one', 'two:three']

dict([(1, 'one'), (2, 'two')])

{1: 'one', 2: 'two'}

'blah'.center(80)

'                                      blah                                      '

'xxx\tyyy'.expandtabs()

'xxx     yyy'

More About Lists

l = [4, 2, 3.6]

l.sort()

l

[2, 3.6, 4]

l = [2, 'eins']

try:
    l.sort()
except Exception as e:
    print(type(e), e)

<class 'TypeError'> '<' not supported between instances of 'str' and 'int'

l = [2, 1, 3, 7, 4]

l.sort(reverse=True)

l

[7, 4, 3, 2, 1]

l.reverse()

l

[1, 2, 3, 4, 7]

[i**2 for i in l]

[1, 4, 9, 16, 49]

More About Dictionaries

d = {'one': 1, 'two': 2}

d['one']

1

if 'three' in d:
    v = d['three']
else:
    v = 3
v

3

v = d.get('three', 3)

print(v)

3

if 'three' in d:
    v = d['three']
else:
    d['three'] = 3
    v = d['three']

del d['three']

d.setdefault('three', 3)

3

Pythonicity (enumerate())

l = ['Joerg', 'Caro', 'Johanna', 'Philipp']

lineno = 0
for name in l:
    print(lineno, name)
    lineno += 1

0 Joerg
1 Caro
2 Johanna
3 Philipp

for elem in enumerate(l):
    print(elem)

(0, 'Joerg')
(1, 'Caro')
(2, 'Johanna')
(3, 'Philipp')

for lineno, name in enumerate(l):
    print(lineno, name)

0 Joerg
1 Caro
2 Johanna
3 Philipp

pandas, matplotlib

import pandas

df = pandas.read_csv('data.csv', encoding='utf-16', delimiter='\t')

df

	Scan	Zeit	101 <MP_left 1> (C)	102 <MP_left 2> (C)	103 <MP_left 3> (C)	104 <MP_top> (C)	105 <MP_right 1> (C)	106 <MP_righ 2> (C)	107 <MP_righ 3> (C)	108 <Brenner Kupfer> (C)	109 <Brenner Messing> (C)	110 <Koax Oberflaeche 15> (C)	111 <Koax Oberflaeche 100> (C)	112 <Gasduese> (C)	113 <FSC Koax 15> (C)	114 <FSC> (C)	115 <Zellentemp> (C)	117 <Raumtemp> (C)	120 <strom> (VDC)
0	1	01.03.2022 10:15:38	28.540	28.274	29.077	28.347	28.877	28.811	29.313	32.090	31.883	28.746	27.609	23.437	24.716	30.500	23.288	21.219	3.76220
1	2	01.03.2022 10:15:48	28.529	28.260	29.045	28.299	28.828	28.770	29.273	31.964	31.771	28.768	27.668	24.459	24.695	30.465	23.476	21.173	3.77849
2	3	01.03.2022 10:15:58	28.476	28.220	28.994	28.264	28.812	28.727	29.198	31.887	31.655	28.671	27.537	24.225	24.681	30.433	23.482	21.086	3.81216
3	4	01.03.2022 10:16:08	28.465	28.209	28.935	28.210	28.788	28.706	29.126	31.774	31.540	28.615	27.411	23.552	24.657	30.409	23.278	21.154	3.99354
4	5	01.03.2022 10:16:18	28.556	28.255	28.940	28.178	28.922	28.816	29.327	32.300	32.371	28.553	27.445	317.346	24.697	30.511	30.591	21.116	373.92051
...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...
348	349	01.03.2022 11:13:38	50.115	48.607	51.650	45.000	50.949	51.040	53.544	87.077	92.665	51.471	45.354	26.299	33.918	40.816	23.035	20.946	4.82874
349	350	01.03.2022 11:13:48	49.994	48.545	51.467	44.949	50.939	51.011	53.431	86.591	92.075	51.297	45.141	58.909	33.804	40.777	23.006	20.926	4.78855
350	351	01.03.2022 11:13:58	49.933	48.510	51.395	44.929	50.898	50.971	53.314	86.098	91.442	51.036	45.007	181.211	33.701	40.716	22.991	20.991	4.76466
351	352	01.03.2022 11:14:08	49.967	48.447	51.422	44.881	50.816	50.869	52.862	85.583	90.813	50.839	44.909	2.091	33.706	40.655	22.921	21.010	4.64736
352	353	01.03.2022 11:14:18	49.812	48.352	51.316	44.781	50.680	50.827	52.941	85.118	90.164	50.844	44.964	-124.132	33.483	40.594	23.259	20.891	4.65062

353 rows × 19 columns

timestamps = df['Zeit']

timestamps

0      01.03.2022 10:15:38
1      01.03.2022 10:15:48
2      01.03.2022 10:15:58
3      01.03.2022 10:16:08
4      01.03.2022 10:16:18
              ...
348    01.03.2022 11:13:38
349    01.03.2022 11:13:48
350    01.03.2022 11:13:58
351    01.03.2022 11:14:08
352    01.03.2022 11:14:18
Name: Zeit, Length: 353, dtype: object

type(timestamps)

pandas.core.series.Series

from datetime import datetime

def transform_ts(ts):
    dt = datetime.strptime(ts, '%d.%m.%Y %H:%M:%S')
    return dt.timestamp()

transformed_timestamps = timestamps.apply(transform_ts)

transformed_timestamps

0      1.646126e+09
1      1.646126e+09
2      1.646126e+09
3      1.646126e+09
4      1.646126e+09
           ...
348    1.646130e+09
349    1.646130e+09
350    1.646130e+09
351    1.646130e+09
352    1.646130e+09
Name: Zeit, Length: 353, dtype: float64

df['Zeit'] = transformed_timestamps

df

	Scan	Zeit	101 <MP_left 1> (C)	102 <MP_left 2> (C)	103 <MP_left 3> (C)	104 <MP_top> (C)	105 <MP_right 1> (C)	106 <MP_righ 2> (C)	107 <MP_righ 3> (C)	108 <Brenner Kupfer> (C)	109 <Brenner Messing> (C)	110 <Koax Oberflaeche 15> (C)	111 <Koax Oberflaeche 100> (C)	112 <Gasduese> (C)	113 <FSC Koax 15> (C)	114 <FSC> (C)	115 <Zellentemp> (C)	117 <Raumtemp> (C)	120 <strom> (VDC)
0	1	1.646126e+09	28.540	28.274	29.077	28.347	28.877	28.811	29.313	32.090	31.883	28.746	27.609	23.437	24.716	30.500	23.288	21.219	3.76220
1	2	1.646126e+09	28.529	28.260	29.045	28.299	28.828	28.770	29.273	31.964	31.771	28.768	27.668	24.459	24.695	30.465	23.476	21.173	3.77849
2	3	1.646126e+09	28.476	28.220	28.994	28.264	28.812	28.727	29.198	31.887	31.655	28.671	27.537	24.225	24.681	30.433	23.482	21.086	3.81216
3	4	1.646126e+09	28.465	28.209	28.935	28.210	28.788	28.706	29.126	31.774	31.540	28.615	27.411	23.552	24.657	30.409	23.278	21.154	3.99354
4	5	1.646126e+09	28.556	28.255	28.940	28.178	28.922	28.816	29.327	32.300	32.371	28.553	27.445	317.346	24.697	30.511	30.591	21.116	373.92051
...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...
348	349	1.646130e+09	50.115	48.607	51.650	45.000	50.949	51.040	53.544	87.077	92.665	51.471	45.354	26.299	33.918	40.816	23.035	20.946	4.82874
349	350	1.646130e+09	49.994	48.545	51.467	44.949	50.939	51.011	53.431	86.591	92.075	51.297	45.141	58.909	33.804	40.777	23.006	20.926	4.78855
350	351	1.646130e+09	49.933	48.510	51.395	44.929	50.898	50.971	53.314	86.098	91.442	51.036	45.007	181.211	33.701	40.716	22.991	20.991	4.76466
351	352	1.646130e+09	49.967	48.447	51.422	44.881	50.816	50.869	52.862	85.583	90.813	50.839	44.909	2.091	33.706	40.655	22.921	21.010	4.64736
352	353	1.646130e+09	49.812	48.352	51.316	44.781	50.680	50.827	52.941	85.118	90.164	50.844	44.964	-124.132	33.483	40.594	23.259	20.891	4.65062

353 rows × 19 columns

df.columns

Index(['Scan', 'Zeit', '101 <MP_left 1> (C)', '102 <MP_left 2> (C)',
       '103 <MP_left 3> (C)', '104 <MP_top> (C)', '105 <MP_right 1> (C)',
       '106 <MP_righ 2> (C)', '107 <MP_righ 3> (C)',
       '108 <Brenner Kupfer> (C)', '109 <Brenner Messing> (C)',
       '110 <Koax Oberflaeche 15> (C)', '111 <Koax Oberflaeche 100> (C)',
       '112 <Gasduese> (C)', '113 <FSC Koax 15> (C)', '114 <FSC> (C)',
       '115 <Zellentemp> (C)', '117 <Raumtemp> (C)', '120 <strom> (VDC)'],
      dtype='object')

df[df.columns[2]]

0      28.540
1      28.529
2      28.476
3      28.465
4      28.556
        ...
348    50.115
349    49.994
350    49.933
351    49.967
352    49.812
Name: 101 <MP_left 1> (C), Length: 353, dtype: float64

timestamps = df[df.columns[1]]

mpleft_1 = df[df.columns[2]]

mpleft_2 = df[df.columns[3]]

%matplotlib inline

import matplotlib.pyplot as plt

plt.plot(timestamps, mpleft_1)

[<matplotlib.lines.Line2D at 0x7f48ab74abf0>]

plt.plot(timestamps, mpleft_2)

[<matplotlib.lines.Line2D at 0x7f48a96648b0>]

exec()

code = 'print("hallo")'

exec(code)

hallo

code = '''
def add(l, r):
    return l+r
'''

exec(code)

add(1, 2)

3

code = '''
eine_variable = 1
noch_eine_variable = 2
'''

context = {}

exec(code, context)

context['eine_variable']

1

context['noch_eine_variable']

2

Comprehensions (List, Dictionary, Set)

List Comprehension

l = [0, 1, 2, 3, 4, 5]

l = list(range(6))

l

[0, 1, 2, 3, 4, 5]

squares = []
for i in l:
    squares.append(i**2)
squares

[0, 1, 4, 9, 16, 25]

squares = [i**2 for i in l]
squares

[0, 1, 4, 9, 16, 25]

even_squares = [i**2 for i in l if i%2 == 0]
even_squares

[0, 4, 16]

filter()

l

[0, 1, 2, 3, 4, 5]

def even_pred(n):
    return n%2 == 0
even = filter(even_pred, l)

even

<filter at 0x7f48a9505b40>

for elem in even:
    print(elem)

0
2
4

even = [i for i in l if i%2 == 0]

even

[0, 2, 4]

Generator Expression

even = (i for i in l if i%2 == 0)

even

<generator object <genexpr> at 0x7f48a95250e0>

for elem in even:
    print(elem)

0
2
4

Dictionary Comprehension

l

[0, 1, 2, 3, 4, 5]

dict i:i**2

squaredict = {i: i**2 for i in l}

squaredict

{0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25}

Set Comprehension

squaresset = {i**2 for i in range(15)}

squaresset

{0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196}

zip(), And Dictionaries

keys = ['one', 'two', 'three']
values = range(1,4)

{k: v for k, v in zip(keys, values)}

{'one': 1, 'two': 2, 'three': 3}

for elem in zip(keys, values):
    print(elem)

('one', 1)
('two', 2)
('three', 3)

values = range(6)

for elem in zip(keys, (v for i, v in enumerate(values) if i%2 == 0)):
    print(elem)

('one', 0)
('two', 2)
('three', 4)

File IO

f = open('/etc/passwd')

f.read(10)

'root:x:0:0'

f.read(5)

':root'

f.close()

with open('/etc/passwd') as f:
    print(f.readline())

root:x:0:0:root:/root:/bin/bash

f = open('/etc/passwd')

f.readline()

'root:x:0:0:root:/root:/bin/bash\n'

f.readline()

'bin:x:1:1:bin:/bin:/sbin/nologin\n'

for line in f:
    print(line)

daemon:x:2:2:daemon:/sbin:/sbin/nologin

adm:x:3:4:adm:/var/adm:/sbin/nologin

lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin

sync:x:5:0:sync:/sbin:/bin/sync

shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown

halt:x:7:0:halt:/sbin:/sbin/halt

mail:x:8:12:mail:/var/spool/mail:/sbin/nologin

operator:x:11:0:operator:/root:/sbin/nologin

games:x:12:100:games:/usr/games:/sbin/nologin

ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin

nobody:x:65534:65534:Kernel Overflow User:/:/sbin/nologin

dbus:x:81:81:System message bus:/:/sbin/nologin

apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin

tss:x:59:59:Account used for TPM access:/dev/null:/sbin/nologin

systemd-network:x:192:192:systemd Network Management:/:/usr/sbin/nologin

systemd-oom:x:999:999:systemd Userspace OOM Killer:/:/usr/sbin/nologin

systemd-resolve:x:193:193:systemd Resolver:/:/usr/sbin/nologin

qemu:x:107:107:qemu user:/:/sbin/nologin

polkitd:x:998:997:User for polkitd:/:/sbin/nologin

avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin

unbound:x:997:995:Unbound DNS resolver:/etc/unbound:/sbin/nologin

nm-openconnect:x:996:994:NetworkManager user for OpenConnect:/:/sbin/nologin

geoclue:x:995:993:User for geoclue:/var/lib/geoclue:/sbin/nologin

usbmuxd:x:113:113:usbmuxd user:/:/sbin/nologin

gluster:x:994:992:GlusterFS daemons:/run/gluster:/sbin/nologin

rtkit:x:172:172:RealtimeKit:/proc:/sbin/nologin

chrony:x:993:990::/var/lib/chrony:/sbin/nologin

saslauth:x:992:76:Saslauthd user:/run/saslauthd:/sbin/nologin

dnsmasq:x:991:989:Dnsmasq DHCP and DNS server:/var/lib/dnsmasq:/sbin/nologin

rpc:x:32:32:Rpcbind Daemon:/var/lib/rpcbind:/sbin/nologin

colord:x:990:988:User for colord:/var/lib/colord:/sbin/nologin

rpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologin

openvpn:x:989:987:OpenVPN:/etc/openvpn:/sbin/nologin

nm-openvpn:x:988:986:Default user for running openvpn spawned by NetworkManager:/:/sbin/nologin

pipewire:x:987:985:PipeWire System Daemon:/var/run/pipewire:/sbin/nologin

abrt:x:173:173::/etc/abrt:/sbin/nologin

flatpak:x:986:983:User for flatpak system helper:/:/sbin/nologin

gdm:x:42:42:GNOME Display Manager:/var/lib/gdm:/sbin/nologin

gnome-initial-setup:x:985:982::/run/gnome-initial-setup/:/sbin/nologin

vboxadd:x:984:1::/var/run/vboxadd:/sbin/nologin

sshd:x:74:74:Privilege-separated SSH:/usr/share/empty.sshd:/sbin/nologin

tcpdump:x:72:72::/:/sbin/nologin

jfasch:x:1000:1000:Jörg Faschingbauer:/home/jfasch:/bin/bash

systemd-coredump:x:978:978:systemd Core Dumper:/:/usr/sbin/nologin

systemd-timesync:x:977:977:systemd Time Synchronization:/:/usr/sbin/nologin

mosquitto:x:976:976:Mosquitto Broker:/etc/mosquitto:/sbin/nologin

f = open('/etc/passwd', encoding='ascii')

try:
    f.read()
except Exception as e:
    print(type(e), e)

<class 'UnicodeDecodeError'> 'ascii' codec can't decode byte 0xc3 in position 2440: ordinal not in range(128)