NBA_02_Listen_Dezimalzahlen_Werkzeuge

(c) 2023 Technische Hochschule Augsburg - Fakultät für Informatik - Prof.Dr.Nik Klever - Impressum

Listen

array

from array import array
a = array("H", [1,2,3,4])
a

array('H', [1, 2, 3, 4])

with open("binär.bin","wb") as f:
    a.tofile(f)

!hexdump binär.bin -C

00000000  01 00 02 00 03 00 04 00                           |........|
00000008

a = array("H", range(65,67))
a

array('H', [65, 66])

with open("binär.bin","wb") as f:
    a.tofile(f)

!hexdump binär.bin -C

00000000  41 00 42 00                                       |A.B.|
00000004

ord("B")

66

hex(ord("B"))

'0x42'

collections

deque

from collections import deque
d = deque([1,2,3])
print("Warteschlange:",d)

Warteschlange: deque([1, 2, 3])

n = 4
d.append(n)
print("Warteschlange:",d)

Warteschlange: deque([1, 2, 3, 4])

b = d.popleft()
b

1

print("Warteschlange:",d)

Warteschlange: deque([2, 3, 4])

OrderedDict

from collections import OrderedDict
d = {"Banane": 3, "Zitrone": 12, "Kiwi": 5, "Orange":15}
od = OrderedDict(d)
od

OrderedDict([('Kiwi', 5), ('Orange', 15), ('Banane', 3), ('Zitrone', 12)])

bisect

import bisect
tupelliste = [(1,"Apfel"),(5,"Banane"),(8,"Zitrone")]
bisect.insort(tupelliste,(3,"Birne"))
tupelliste

[(1, 'Apfel'), (3, 'Birne'), (5, 'Banane'), (8, 'Zitrone')]

heapq

    heap[k] <= heap[2*k+1] and heap[k] <= heap[2*k+2] # für alle k >= 0; heap[x] = unendlich, wenn x > len(heap)

from heapq import heapify, heappop, heappush

def testheap(data):
    for i in range(len(data)):
        compare = [True, True]
        for j in 0,1:
            if 2*i+j+1 < len(data):
                compare[j] = data[i] <= data[2*i+j+1]
        if not (compare[0] and compare[1]):
            print("data is not a heap")
            break
    else:
        print("data is a heap")

data = [1,3,5,7,9,2,4,6,8,0]
print(data)
testheap(data)

[1, 3, 5, 7, 9, 2, 4, 6, 8, 0]
data is not a heap

heapify(data)
print(data)
testheap(data)

[0, 1, 2, 6, 3, 5, 4, 7, 8, 9]
data is a heap

Dezimalzahlen

from decimal import *
round(Decimal("0.70")*Decimal("1.05"), 2)

Decimal('0.74')

round(0.70*1.05,2)

0.73

Decimal("1.00") % Decimal(".10")

Decimal('0.00')

1.0 % 0.1

0.09999999999999995

sum([Decimal("0.1")]*10) == Decimal("1.0")

True

sum([0.1]*10) == 1.0

False

sum([0.1]*10) - 1.0

-1.1102230246251565e-16

getcontext()

Context(prec=28, rounding=ROUND_HALF_EVEN, Emin=-999999, Emax=999999, capitals=1, clamp=0, flags=[Inexact, Rounded], traps=[InvalidOperation, DivisionByZero, Overflow])

getcontext().prec=36
Decimal(1) / Decimal(7)

Decimal('0.142857142857142857142857142857142857')