2023-03-13

l = [1,2,3,4, 'fuenf']
for element in l:
    print(element)

1
2
3
4
fuenf

l

[1, 2, 3, 4, 'fuenf']

print(type(l))

<class 'list'>

i = 42

i

42

print(type(i))

<class 'int'>

exec('print("hallo")')

hallo

Syntax

Comment vs Docstring

# das ist ein kommentar

i = 42 # das ist auch ein kommentar

i

42

# das ist die funktion foo, die hoechst komplex ist und
# die parameter a und b nimmt, die idealerweise integers  sein sollten
def foo(a, b):
    return a+b

def foo(a, b):
    'das ist die funktion foo, die hoechst komplex ist und die parameter a und b nimmt, die idealerweise integers  sein sollten'
    return a+b

foo.__doc__

'das ist die funktion foo, die hoechst komplex ist und die parameter a und b nimmt, die idealerweise integers  sein sollten'

help(foo)

Help on function foo in module __main__:

foo(a, b)
    das ist die funktion foo, die hoechst komplex ist und die parameter a und b nimmt, die idealerweise integers  sein sollten

foo(1, 2)

3

add = foo

add(2, 3)

5

add = [1,2,3]

try:
    add(2,3)
except Exception as e:
    print(e, type(e))

'list' object is not callable <class 'TypeError'>

Tuple Unpacking

l = [1, 'zwei', 3.0]

a, b, c = l

a

1

b

'zwei'

c

3.0

a, *rest = l

a

1

rest

['zwei', 3.0]

try:
    a, b = l
except Exception as e:
    print(e, type(e))

too many values to unpack (expected 2) <class 'ValueError'>

1, 2

(1, 2)

a, b

(1, 'zwei')

tmp = a
a = b
b = tmp

a, b

('zwei', 1)

a, b = b, a

Mutable? Immutable?

a = 42

id(a)

140480285361680

b = a

id(b)

140480285361680

a += 1

b

42

a

43

Integers

i = 2**64 - 1

i

18446744073709551615

hex(i)

'0xffffffffffffffff'

i += 1

i

18446744073709551616

hex(i)

'0x10000000000000000'

i += 1

i = 2**100

i

1267650600228229401496703205376

2**10000

19950631168807583848837421626835850838234968318861924548520089498529438830221946631919961684036194597899331129423209124271556491349413781117593785932096323957855730046793794526765246551266059895520550086918193311542508608460618104685509074866089624888090489894838009253941633257850621568309473902556912388065225096643874441046759871626985453222868538161694315775629640762836880760732228535091641476183956381458969463899410840960536267821064621427333394036525565649530603142680234969400335934316651459297773279665775606172582031407994198179607378245683762280037302885487251900834464581454650557929601414833921615734588139257095379769119277800826957735674444123062018757836325502728323789270710373802866393031428133241401624195671690574061419654342324638801248856147305207431992259611796250130992860241708340807605932320161268492288496255841312844061536738951487114256315111089745514203313820202931640957596464756010405845841566072044962867016515061920631004186422275908670900574606417856951911456055068251250406007519842261898059237118054444788072906395242548339221982707404473162376760846613033778706039803413197133493654622700563169937455508241780972810983291314403571877524768509857276937926433221599399876886660808368837838027643282775172273657572744784112294389733810861607423253291974813120197604178281965697475898164531258434135959862784130128185406283476649088690521047580882615823961985770122407044330583075869039319604603404973156583208672105913300903752823415539745394397715257455290510212310947321610753474825740775273986348298498340756937955646638621874569499279016572103701364433135817214311791398222983845847334440270964182851005072927748364550578634501100852987812389473928699540834346158807043959118985815145779177143619698728131459483783202081474982171858011389071228250905826817436220577475921417653715687725614904582904992461028630081535583308130101987675856234343538955409175623400844887526162643568648833519463720377293240094456246923254350400678027273837755376406726898636241037491410966718557050759098100246789880178271925953381282421954028302759408448955014676668389697996886241636313376393903373455801407636741877711055384225739499110186468219696581651485130494222369947714763069155468217682876200362777257723781365331611196811280792669481887201298643660768551639860534602297871557517947385246369446923087894265948217008051120322365496288169035739121368338393591756418733850510970271613915439590991598154654417336311656936031122249937969999226781732358023111862644575299135758175008199839236284615249881088960232244362173771618086357015468484058622329792853875623486556440536962622018963571028812361567512543338303270029097668650568557157505516727518899194129711337690149916181315171544007728650573189557450920330185304847113818315407324053319038462084036421763703911550639789000742853672196280903477974533320468368795868580237952218629120080742819551317948157624448298518461509704888027274721574688131594750409732115080498190455803416826949787141316063210686391511681774304792596709376

3/2

1.5

3//2

1

10%2

0

Lists

l = list()
l = []
l = [1,2,3]

len(l)

3

id(l)

140479638276224

l.append('vier')
id(l)

140479638276224

l.extend([5, 'sechs'])

l

[1, 2, 3, 'vier', 5, 'sechs']

l.append([7, 'acht'])

l

[1, 2, 3, 'vier', 5, 'sechs', [7, 'acht']]

l.append(l)

l

[1, 2, 3, 'vier', 5, 'sechs', [7, 'acht'], [...]]

l[1]

2

l[1] = 'zwei'

l

[1, 'zwei', 3, 'vier', 5, 'sechs', [7, 'acht'], [...]]

'zwei' in l

True

if 'zwei' in l:
    print('yay')

yay

Tuples

t = (1,2,3)

type(t)

tuple

id(t)

140480203220736

t[1]

2

try:
    t[1] = 'zwei'
except Exception as e:
    print(e, type(e))

'tuple' object does not support item assignment <class 'TypeError'>

try:
    t.append('vier')
except Exception as e:
    print(e, type(e))

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

t += (1,2,3)

id(t)

140480210406176

Dictionary

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

len(d)

2

d['one']

1

d['drei'] = 'three'

d['drei']

'three'

d[4] = 'vier'

hash(4)

4

hash('drei')

-7940943354778932823

try:
    d[[1,2,3]] = True
except Exception as e:
    print(e, type(e))

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

d

{'one': 1, 'two': 2, 'drei': 'three', 4: 'vier'}

len(d)

4

'two' in d

True

del d['two']

'two' in d

False

Search by value?

for k, v in d.items():
    if v == 1:
        print(k)

one

Exercises

l = []

l.append(True)

l

[True]

s = '99'

i = int(s)

i

99

DataType Conversiosn

s = '123'

i = int(s)

print(type(i))

<class 'int'>

i

123

s = 'abc'

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

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

int(s, 16)

2748

i

123

s = str(i)

print(type(s))

<class 'str'>

l = [1,2,3, 'vier']
print(type(l))

<class 'list'>

s

'123'

s[1]

'2'

list()

[]

list('abc')

['a', 'b', 'c']

try:
    list(666)
except Exception as e:
    print(e, type(s))

'int' object is not iterable <class 'str'>

l = list()
l.append('abc')
l

['abc']

list(['abc'])

['abc']

['abc']

['abc']

l = list(range(3))

l

[0, 1, 2]

for element in l:
    print(element)

0
1
2

1 in l

True

2 in l

True

3 in l

False

if

i = 2

if i == 2:
    print('yay')

yay

if i == 3:
    print('yay')

while

sum of numbers 1..100

summe = 0
number = 1
while number <= 100:
    summe += number
    number += 1
summe

5050

sum(range(1, 101))

5050

i = 42
while i != 42:
    print('noch immer keine antwort')

import random

while True:
    eyes = random.randrange(1, 7)
    if eyes == 6:
        print('hooray!')
        break
    else:
        print('mist:', eyes)

mist: 4
hooray!

n_tries = 0
while n_tries < 6:
    eyes = random.randrange(1, 7)
    if eyes == 6:
        print('hooray!')
        break
    n_tries += 1
else:
    print('versager!')

versager!

range()

for element in range(5):
    print(element)

0
1
2
3
4

for element in [0,1,2,3,4]:
    print(element)

0
1
2
3
4

r = range(5)

r

range(0, 5)

it = iter(r)

it

<range_iterator at 0x7fc4189e7c90>

next(it)

0

next(it)

1

next(it)

2

next(it)

3

next(it)

4

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

 <class 'StopIteration'>

datetime

import datetime

start = datetime.datetime(year=2023, month=3, day=13, hour=9)

start

datetime.datetime(2023, 3, 13, 9, 0)

step = datetime.timedelta(hours=8)

step

datetime.timedelta(seconds=28800)

start += step

start

datetime.datetime(2023, 3, 13, 17, 0)

start += datetime.timedelta(days=1)

start

datetime.datetime(2023, 3, 14, 17, 0)

datetime.datetime.now()

datetime.datetime(2023, 3, 14, 10, 6, 17, 237988)

def produce_days(start):
    next = start
    while True:
        yield next
        next += datetime.timedelta(days=1)

for day in produce_days(start=datetime.datetime.now()):
    print(day)
    if day > datetime.datetime(year=2023, month=4, day=1):
        break

2023-03-14 10:11:25.374557
2023-03-15 10:11:25.374557
2023-03-16 10:11:25.374557
2023-03-17 10:11:25.374557
2023-03-18 10:11:25.374557
2023-03-19 10:11:25.374557
2023-03-20 10:11:25.374557
2023-03-21 10:11:25.374557
2023-03-22 10:11:25.374557
2023-03-23 10:11:25.374557
2023-03-24 10:11:25.374557
2023-03-25 10:11:25.374557
2023-03-26 10:11:25.374557
2023-03-27 10:11:25.374557
2023-03-28 10:11:25.374557
2023-03-29 10:11:25.374557
2023-03-30 10:11:25.374557
2023-03-31 10:11:25.374557
2023-04-01 10:11:25.374557

l = [666, 42]
i = 42

i != l

True

i in l

True

i not in l

False

not i in l

False

6 % 3

0

6 % 2

0

7 % 2

1

7 % 3

1

7 % 4

3

7 % 5

2

7 % 6

1

Comprehensions

l = [3, 4, 1, 6]

l_mal_2 = []
for element in l:
    l_mal_2.append(element*2)
l_mal_2

[6, 8, 2, 12]

[element*2 for element in l]

[6, 8, 2, 12]

[element*2 for element in l if element%2==0]

[8, 12]

References, (Im)mutability

a = 42

id(a)

140480285361680

b = a

id(b)

140480285361680

a += 1

id(a)

140480285361712

b

42

id(b)

140480285361680

l1 = [42, 'xy', 13]
id(l1)

140479638477760

l2 = l1

id(l2)

140479638477760

l1.append(666)
l1

[42, 'xy', 13, 666]

id(l1)

140479638477760

id(l2)

140479638477760

l2

[42, 'xy', 13, 666]

l3 = l1[:]

l3

[42, 'xy', 13, 666]

l1

[42, 'xy', 13, 666]

id(l1)

140479638477760

id(l3)

140479638427520

l3.append('nochwas')
l3

[42, 'xy', 13, 666, 'nochwas']

l1

[42, 'xy', 13, 666]

Nested lists?

l4 = [1, [2,3,4], 5]
len(l4)

3

l5 = l4[:]

id(l4)

140480202528192

id(l5)

140479638428736

l4[1].append(666)

l5

[1, [2, 3, 4, 666], 5]

id(l4[1])

140480203212992

id(l5[1])

140480203212992

import copy

l6 = copy.deepcopy(l5)

l6

[1, [2, 3, 4, 666], 5]

Functions

def maximum(a, b):
    'extremely complex function'
    if a < b:
        return b
    else:
        return a

maximum(1, 2)

2

maximum(1.5, 2.5)

2.5

maximum('abc', 'def')

'def'

maximum([1,2], [3,4])

[3, 4]

maximum([1,2], [1,4])

[1, 4]

try:
    maximum('abc', 666)
except Exception as e:
    print(e, type(e))

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

True < False

False

print(type(maximum))

<class 'function'>

maximum.__doc__

'extremely complex function'

a = maximum

a(1,2)

2

id(a)

140479598069936

id(maximum)

140479598069936

Classes?

class Person:
    def __init__(self, firstname, lastname, age):
        self.firstname = firstname
        self.lastname = lastname
        self.age = age
    def fullname(self):
        return self.firstname + ' ' + self.lastname

joerg = Person('Joerg', 'Faschingbauer', 56)

type(joerg)

__main__.Person

joerg.fullname()

'Joerg Faschingbauer'

def is_old(p):
    if p.age > 50:
        return True
    else:
        return False

is_old(joerg)

True

Person.old = is_old

joerg = Person('Joerg', 'Faschingbauer', 56)

joerg.old()

True

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

d['one']

1

d['three']

---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
/tmp/ipykernel_370861/4290492544.py in <module>
----> 1 d['three']

KeyError: 'three'

Strings

s = 'abc'

s = "abc"

s = 'abc\'def'
s

"abc'def"

s = "abc'def"
s

"abc'def"

s = 'C:\some\name'

print(s)

C:\some
ame

s = r'C:\some\name'
print(s)

C:\some\name

s = '12345'
s.isdigit()

True

s = 'abc123'
s.isdigit()

False

'abc'.center(50)

'                       abc                        '

s = 'Mississippi'
s.count('ss')

2

s.count('pp')

1

'file.csv'.endswith('.csv')

True

'boot'.endswith('t')

True

'boot'.count('oo') > 0

True

'boot'.find('oo') >= 0

True

'oo' in 'boot'

True

'boot'.find('oo')

1

'boot'.find('xxx')

-1

try:
    'boot'.index('xxx')
except Exception as e:
    print(e, type(e))

substring not found <class 'ValueError'>

s = 'Bezahlung Karte   blah |BILLA DANKT blah blah     |BILL blah'

fields = s.split('|')

fields

['Bezahlung Karte   blah ', 'BILLA DANKT blah blah     ', 'BILL blah']

';'.join(fields)

'Bezahlung Karte   blah ;BILLA DANKT blah blah     ;BILL blah'

s = '    \t\n   xxx \n\n\n\t    '
s.strip()

'xxx'

Lists

l = [1,2,'drei']
l.append(666)

l

[1, 2, 'drei', 666]

l.extend(['noch', 'was'])
l

[1, 2, 'drei', 666, 'noch', 'was']

l.extend('abc')
l

[1, 2, 'drei', 666, 'noch', 'was', 'a', 'b', 'c']

l.pop(3)

666

l

[1, 2, 'drei', 'noch', 'was', 'a', 'b', 'c']

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

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

l.reverse()

l

['c', 'b', 'a', 'was', 'noch', 'drei', 2, 1]

reversed(l)

<list_reverseiterator at 0x7fc4189e5030>

l = [1,2,3,7,100]
[elem**2 for elem in l]

[1, 4, 9, 49, 10000]

[elem**2 for elem in l if elem%2==0]

[4, 10000]

Dictionaries

d = {}

d['one'] = 1

d

{'one': 1}

d['one'] = 1.1

d

{'one': 1.1}

d['one']

1.1

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

'two' <class 'KeyError'>

if d.get('two') is None:
    print('nicht drin')
else:
    print('yay')

nicht drin

v = d.get('two', 2)
v

2

d

{'one': 1.1}

v = d.setdefault('two', 2)
v

2

d

{'one': 1.1, 'two': 2}

del d['two']
d

{'one': 1.1}

d.update({'two': 2, 'three': 3, 'one': 1})

d

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

for elem in d:
    print(elem)

one
two
three

for k in d.keys():
    print(k)

one
two
three

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

1
2
3

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

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

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

key: one , value: 1
key: two , value: 2
key: three , value: 3

for elem in d.items():    # semi-manual tuple unpacking
    k, v = elem
    print('key:', k, ', value:', v)

key: one , value: 1
key: two , value: 2
key: three , value: 3

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

key: one , value: 1
key: two , value: 2
key: three , value: 3

'one' in d

True

dict

dict

l = [('one', 1), ('two', 2)]
d = dict(l)

d

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

Set

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

s1.isdisjoint(s2)

False

s1 < s2

True

s3 = {0,1,2,3}
s3 < s2

False

s3 | s2

{0, 1, 2, 3, 4}

File IO

f = open('/etc/passwd')
f

<_io.TextIOWrapper name='/etc/passwd' mode='r' encoding='UTF-8'>

f.read()

'root:x:0:0:root:/root:/bin/bash\nbin:x:1:1:bin:/bin:/sbin/nologin\ndaemon:x:2:2:daemon:/sbin:/sbin/nologin\nadm:x:3:4:adm:/var/adm:/sbin/nologin\nlp:x:4:7:lp:/var/spool/lpd:/sbin/nologin\nsync:x:5:0:sync:/sbin:/bin/sync\nshutdown:x:6:0:shutdown:/sbin:/sbin/shutdown\nhalt:x:7:0:halt:/sbin:/sbin/halt\nmail:x:8:12:mail:/var/spool/mail:/sbin/nologin\noperator:x:11:0:operator:/root:/sbin/nologin\ngames:x:12:100:games:/usr/games:/sbin/nologin\nftp:x:14:50:FTP User:/var/ftp:/sbin/nologin\nnobody:x:65534:65534:Kernel Overflow User:/:/sbin/nologin\ndbus:x:81:81:System message bus:/:/sbin/nologin\napache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin\ntss:x:59:59:Account used for TPM access:/dev/null:/sbin/nologin\nsystemd-network:x:192:192:systemd Network Management:/:/usr/sbin/nologin\nsystemd-oom:x:999:999:systemd Userspace OOM Killer:/:/usr/sbin/nologin\nsystemd-resolve:x:193:193:systemd Resolver:/:/usr/sbin/nologin\nqemu:x:107:107:qemu user:/:/sbin/nologin\npolkitd:x:998:997:User for polkitd:/:/sbin/nologin\navahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin\nunbound:x:997:995:Unbound DNS resolver:/etc/unbound:/sbin/nologin\nnm-openconnect:x:996:994:NetworkManager user for OpenConnect:/:/sbin/nologin\ngeoclue:x:995:993:User for geoclue:/var/lib/geoclue:/sbin/nologin\nusbmuxd:x:113:113:usbmuxd user:/:/sbin/nologin\ngluster:x:994:992:GlusterFS daemons:/run/gluster:/sbin/nologin\nrtkit:x:172:172:RealtimeKit:/proc:/sbin/nologin\nchrony:x:993:990::/var/lib/chrony:/sbin/nologin\nsaslauth:x:992:76:Saslauthd user:/run/saslauthd:/sbin/nologin\ndnsmasq:x:991:989:Dnsmasq DHCP and DNS server:/var/lib/dnsmasq:/sbin/nologin\nrpc:x:32:32:Rpcbind Daemon:/var/lib/rpcbind:/sbin/nologin\ncolord:x:990:988:User for colord:/var/lib/colord:/sbin/nologin\nrpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologin\nopenvpn:x:989:987:OpenVPN:/etc/openvpn:/sbin/nologin\nnm-openvpn:x:988:986:Default user for running openvpn spawned by NetworkManager:/:/sbin/nologin\npipewire:x:987:985:PipeWire System Daemon:/var/run/pipewire:/sbin/nologin\nabrt:x:173:173::/etc/abrt:/sbin/nologin\nflatpak:x:986:983:User for flatpak system helper:/:/sbin/nologin\ngdm:x:42:42:GNOME Display Manager:/var/lib/gdm:/sbin/nologin\ngnome-initial-setup:x:985:982::/run/gnome-initial-setup/:/sbin/nologin\nvboxadd:x:984:1::/var/run/vboxadd:/sbin/nologin\nsshd:x:74:74:Privilege-separated SSH:/usr/share/empty.sshd:/sbin/nologin\ntcpdump:x:72:72::/:/sbin/nologin\njfasch:x:1000:1000:Joerg Faschingbauer:/home/jfasch:/bin/bash\nsystemd-coredump:x:978:978:systemd Core Dumper:/:/usr/sbin/nologin\nsystemd-timesync:x:977:977:systemd Time Synchronization:/:/usr/sbin/nologin\nmosquitto:x:976:976:Mosquitto Broker:/etc/mosquitto:/sbin/nologin\n'

f = open('/etc/passwd')
f

<_io.TextIOWrapper name='/etc/passwd' mode='r' encoding='UTF-8'>

f.readlines()

['root:x:0:0:root:/root:/bin/bash\n',
 'bin:x:1:1:bin:/bin:/sbin/nologin\n',
 'daemon:x:2:2:daemon:/sbin:/sbin/nologin\n',
 'adm:x:3:4:adm:/var/adm:/sbin/nologin\n',
 'lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin\n',
 'sync:x:5:0:sync:/sbin:/bin/sync\n',
 'shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown\n',
 'halt:x:7:0:halt:/sbin:/sbin/halt\n',
 'mail:x:8:12:mail:/var/spool/mail:/sbin/nologin\n',
 'operator:x:11:0:operator:/root:/sbin/nologin\n',
 'games:x:12:100:games:/usr/games:/sbin/nologin\n',
 'ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin\n',
 'nobody:x:65534:65534:Kernel Overflow User:/:/sbin/nologin\n',
 'dbus:x:81:81:System message bus:/:/sbin/nologin\n',
 'apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin\n',
 'tss:x:59:59:Account used for TPM access:/dev/null:/sbin/nologin\n',
 'systemd-network:x:192:192:systemd Network Management:/:/usr/sbin/nologin\n',
 'systemd-oom:x:999:999:systemd Userspace OOM Killer:/:/usr/sbin/nologin\n',
 'systemd-resolve:x:193:193:systemd Resolver:/:/usr/sbin/nologin\n',
 'qemu:x:107:107:qemu user:/:/sbin/nologin\n',
 'polkitd:x:998:997:User for polkitd:/:/sbin/nologin\n',
 'avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin\n',
 'unbound:x:997:995:Unbound DNS resolver:/etc/unbound:/sbin/nologin\n',
 'nm-openconnect:x:996:994:NetworkManager user for OpenConnect:/:/sbin/nologin\n',
 'geoclue:x:995:993:User for geoclue:/var/lib/geoclue:/sbin/nologin\n',
 'usbmuxd:x:113:113:usbmuxd user:/:/sbin/nologin\n',
 'gluster:x:994:992:GlusterFS daemons:/run/gluster:/sbin/nologin\n',
 'rtkit:x:172:172:RealtimeKit:/proc:/sbin/nologin\n',
 'chrony:x:993:990::/var/lib/chrony:/sbin/nologin\n',
 'saslauth:x:992:76:Saslauthd user:/run/saslauthd:/sbin/nologin\n',
 'dnsmasq:x:991:989:Dnsmasq DHCP and DNS server:/var/lib/dnsmasq:/sbin/nologin\n',
 'rpc:x:32:32:Rpcbind Daemon:/var/lib/rpcbind:/sbin/nologin\n',
 'colord:x:990:988:User for colord:/var/lib/colord:/sbin/nologin\n',
 'rpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologin\n',
 'openvpn:x:989:987:OpenVPN:/etc/openvpn:/sbin/nologin\n',
 'nm-openvpn:x:988:986:Default user for running openvpn spawned by NetworkManager:/:/sbin/nologin\n',
 'pipewire:x:987:985:PipeWire System Daemon:/var/run/pipewire:/sbin/nologin\n',
 'abrt:x:173:173::/etc/abrt:/sbin/nologin\n',
 'flatpak:x:986:983:User for flatpak system helper:/:/sbin/nologin\n',
 'gdm:x:42:42:GNOME Display Manager:/var/lib/gdm:/sbin/nologin\n',
 'gnome-initial-setup:x:985:982::/run/gnome-initial-setup/:/sbin/nologin\n',
 'vboxadd:x:984:1::/var/run/vboxadd:/sbin/nologin\n',
 'sshd:x:74:74:Privilege-separated SSH:/usr/share/empty.sshd:/sbin/nologin\n',
 'tcpdump:x:72:72::/:/sbin/nologin\n',
 'jfasch:x:1000:1000:Joerg Faschingbauer:/home/jfasch:/bin/bash\n',
 'systemd-coredump:x:978:978:systemd Core Dumper:/:/usr/sbin/nologin\n',
 'systemd-timesync:x:977:977:systemd Time Synchronization:/:/usr/sbin/nologin\n',
 'mosquitto:x:976:976:Mosquitto Broker:/etc/mosquitto:/sbin/nologin\n']

f = open('/etc/passwd')
f

<_io.TextIOWrapper name='/etc/passwd' mode='r' encoding='UTF-8'>

for line in f:
    print(line)

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

bin:x:1:1:bin:/bin:/sbin/nologin

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:Joerg 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

String, File IO Exercise

line = ''

if len(line) == 0:
    print('die ist leer')

die ist leer

line = '    \t  '
len(line)

7

line.strip()

''

line = '   xxx      '
line.strip()

'xxx'

line = '    # comment'
line.strip()

'# comment'

eine_variable = line.strip()
eine_variable

'# comment'

eine_variable.startswith('#')

True

line = '  x   y  '
line.replace(' ', '')

'xy'

line = '    #  '
'#' in line

True

l = [2,3,4,1,8,666]

n = len(l)

n

6

3 in l

True

1000 in l     # O(n)

False

s = {2,3,4,1,8,666}

3 in s

True

1000 in s     # O(1)

False

line = 'xxx yyy'

len(line.split(' '))

2

line = 'xxx  yyy'

line.split(' ')

['xxx', '', 'yyy']

line.split()

['xxx', 'yyy']

Pandas

persons = {
    'firstname': ['Joerg',                  'Johanna',        'Caro',              'Philipp'          ],
    'lastname':  ['Faschingbauer',          'Faschingbauer',  'Faschingbauer',     'Lichtenberger'    ],
    'email':     ['jf@faschingbauer.co.at', 'caro@email.com', 'johanna@email.com', 'philipp@email.com'],
    'age':       [56,                       27,               25,                  37                 ],
}

persons

{'firstname': ['Joerg', 'Johanna', 'Caro', 'Philipp'],
 'lastname': ['Faschingbauer',
  'Faschingbauer',
  'Faschingbauer',
  'Lichtenberger'],
 'email': ['jf@faschingbauer.co.at',
  'caro@email.com',
  'johanna@email.com',
  'philipp@email.com'],
 'age': [56, 27, 25, 37]}

import pandas as pd

data = pd.DataFrame(persons)

data

	firstname	lastname	email	age
0	Joerg	Faschingbauer	jf@faschingbauer.co.at	56
1	Johanna	Faschingbauer	caro@email.com	27
2	Caro	Faschingbauer	johanna@email.com	25
3	Philipp	Lichtenberger	philipp@email.com	37

data['firstname']

0      Joerg
1    Johanna
2       Caro
3    Philipp
Name: firstname, dtype: object

type(data['firstname'])

pandas.core.series.Series

data[['firstname', 'lastname']]

	firstname	lastname
0	Joerg	Faschingbauer
1	Johanna	Faschingbauer
2	Caro	Faschingbauer
3	Philipp	Lichtenberger

persons = data

persons.iloc[1]

firstname           Johanna
lastname      Faschingbauer
email        caro@email.com
age                      27
Name: 1, dtype: object

persons.iloc[1, 2]

'caro@email.com'

persons.columns

Index(['firstname', 'lastname', 'email', 'age'], dtype='object')

list(persons.columns)

['firstname', 'lastname', 'email', 'age']

persons2 = persons.set_index('email')

persons2.sort_values('firstname', inplace=True)

persons2

	firstname	lastname	age
email
johanna@email.com	Caro	Faschingbauer	25
jf@faschingbauer.co.at	Joerg	Faschingbauer	56
caro@email.com	Johanna	Faschingbauer	27
philipp@email.com	Philipp	Lichtenberger	37

flt = (persons['lastname'] == 'Faschingbauer')
flt

0     True
1     True
2     True
3    False
Name: lastname, dtype: bool

flt.count()

4

persons.set_index('email', inplace=True)

persons.loc['jf@faschingbauer.co.at']

firstname            Joerg
lastname     Faschingbauer
age                     56
Name: jf@faschingbauer.co.at, dtype: object

persons.loc['jf@faschingbauer.co.at', 'firstname']

'Joerg'

flt = (persons['lastname'] == 'Faschingbauer')
flt

email
jf@faschingbauer.co.at     True
caro@email.com             True
johanna@email.com          True
philipp@email.com         False
Name: lastname, dtype: bool

persons.loc[flt, 'firstname']

email
jf@faschingbauer.co.at      Joerg
caro@email.com            Johanna
johanna@email.com            Caro
Name: firstname, dtype: object

persons['firstname'].isin(['Caro', 'Philipp'])

email
jf@faschingbauer.co.at    False
caro@email.com            False
johanna@email.com          True
philipp@email.com          True
Name: firstname, dtype: bool

(persons['firstname'] == 'Caro') | (persons['firstname'] == 'Philipp')

email
jf@faschingbauer.co.at    False
caro@email.com            False
johanna@email.com          True
philipp@email.com          True
Name: firstname, dtype: bool

persons.reset_index(inplace=True)

persons

	email	firstname	lastname	age
0	jf@faschingbauer.co.at	Joerg	Faschingbauer	56
1	caro@email.com	Johanna	Faschingbauer	27
2	johanna@email.com	Caro	Faschingbauer	25
3	philipp@email.com	Philipp	Lichtenberger	37

persons['email']

0    jf@faschingbauer.co.at
1            caro@email.com
2         johanna@email.com
3         philipp@email.com
Name: email, dtype: object

persons.loc[persons['firstname'].isin(['Caro', 'Philipp'])]

	email	firstname	lastname	age
2	johanna@email.com	Caro	Faschingbauer	25
3	philipp@email.com	Philipp	Lichtenberger	37

persons.loc[persons['firstname'].isin(['Caro', 'Philipp']), 'email']

2    johanna@email.com
3    philipp@email.com
Name: email, dtype: object

persons.loc[persons['firstname'].isin(['Caro', 'Philipp']), 'email'].str.upper()

2    JOHANNA@EMAIL.COM
3    PHILIPP@EMAIL.COM
Name: email, dtype: object

persons['email'] = persons.loc[persons['firstname'].isin(['Caro', 'Philipp']), 'email'].str.upper()

persons

	email	firstname	lastname	age
0	NaN	Joerg	Faschingbauer	56
1	NaN	Johanna	Faschingbauer	27
2	JOHANNA@EMAIL.COM	Caro	Faschingbauer	25
3	PHILIPP@EMAIL.COM	Philipp	Lichtenberger	37

persons.dropna()

	email	firstname	lastname	age
2	JOHANNA@EMAIL.COM	Caro	Faschingbauer	25
3	PHILIPP@EMAIL.COM	Philipp	Lichtenberger	37

persons

	email	firstname	lastname	age
0	NaN	Joerg	Faschingbauer	56
1	NaN	Johanna	Faschingbauer	27
2	JOHANNA@EMAIL.COM	Caro	Faschingbauer	25
3	PHILIPP@EMAIL.COM	Philipp	Lichtenberger	37

persons['firstname'].str.startswith('J').value_counts()

True     2
False    2
Name: firstname, dtype: int64