IB111 Úvod do programovaní
skrze python
2/3.
š Š
Premenná
Premenná
★ ž
★ ž
○
★ č č
★
★
★ ď
loop_count = 0
Premenná
★ ť
loop_count = 0
print(loop_count)
loop_count = 3
print(loop_count)
loop_count = "Text"
print(loop_count)
0
3
Text
Dátový typ
★ ž
★ č
★ č
★
★ ť
★
★
★
Dátové typy
★ ť
type(1)
type("1")
type(1.0)
<class 'int'>
<class 'str'>
<class 'float'>
Dátové typy
★ ť
type(int("1"))
type(str(1))
type(str(1.0))
type(int(1.7))
<class 'int'>
<class 'str'>
<class 'str'>
<class 'int'>
???
Operátory
Príklady
a = 5 + 2 # 5+2
b = 5 - 2 # 5 -2
c = 5 * 2 # 5*2
d = 5.0 // 2#5.0//2
e = 5 / 2 # 5/2
f = 5 % 2 # 5%2
g = 5 ** 2 # 5**2
a = 7
b = 3
c = 10
d = 2
e = 2.5
f = 1
g = 25
Syntax sugar
sum = 0
sum = sum + 1
sum = sum + 2
sum = sum + 3
sum = 0
sum += 1
sum += 2
sum += 3
Porovnávanie
a = 4 == 4
b = 8 != 5
c = 9 < 4
d = 9 <= 4
e = 5 > 3
f = 5 >= 5
a = True
b = True
c = False
d = False
e = True
f = True
Logické spojky
a = True and True
b = True and False
c = False and False
d = True or True
e = True or False
f = False or False
g = not True
h = not False
i = not not True
a = True
b = False
c = False
d = True
e = True
f = False
g = False
h = True
i = True
Kombinácia
★
★ č
★
★ … š ž ť
"10" == str(2 * 5) and 5 ** 4 >= 200
Výstup
Výpis
print("Text")
print(1)
print("a" + "b")
print("a", "b")
print("This","won't","be",end=" ")
print("ended with enter.")
Formátovanie textu
text = "Hello my name is {} and I come
from {}.".format("Slavo", "Slovakia")
print(text)
Hello my name is Slavo and I come from Slovakia.
Vetvenie
Basic if
★
★ žň
★
○
★ č
★ False == 0, 0.0, "", [], (), {}, None, ...
if age >= 18:
print ("You can legally buy alcohol.")
If-else
★
★
★
★ č
if rating > 80:
print("Should be good movie.")
print("Rating:",rating)
else:
print("I wouldn't recommend it.")
# continue...
If-elif
salary = 1000
if salary < 5000:
tax = 0.05
elif salary < 20000:
tax = 0.15
elif salary < 40000:
tax = 0.30
else:
tax = 0.50
Diagram
Zdroj: http://www.programiz.com/python-programming/if-elif-else
Cyklus
Cyklus
★
★ č č č
★
č
★
For
★ č č
★ č
★ ž
for i in range(3):
print(i)
print("I will run just once.")
For
★ č
★ č
★
★ č ž
ž
for i in range(1,10,2):
print(i, end=" ")
# 1 3 5 7 9
While
★
★ ž ť č
★ ť
★ ť ť
i = 0
while i < 3:
print(i)
i += 1
for i in range(3):
print(i)
Kontrola vstupu
choice = input('Like the course ? (y/n)')
while choice != 'y' and choice != 'n':
choice = input("Unexpected input. Enter again:")
break
i = 0
while True:
print(i)
i += 1
if i >= 3:
break # Jump out of 'while' block
print("All right. Off you go.")
Continue
i = 5
while i > 0:
i -= 1
if i == 3:
continue # Jump to condition
print(i)
print("All right. Off you go.")
Procedúry
Procedúry
★ ľ č
★
★
★
○
★
★
○
def procedure(param1, param2):
do_something(param1)
...
do_something(param2)
Procedúry
★ ť ž
○
★ ť
○
def greet(name):
"""
Greets someone
:param name: name of the person to be greeted
"""
print(" Hello {} !".format(name))
Procedúry
★ č ž
š
★
★
greet("students")
But why?
★ ž ť ť ž š š
★
○ š
★ ž ľ ť
★ Ľ š č š
○
Default values
def foo(x, y=3):
print("x =", x)
print("y =", y)
foo(1)
foo(2,5)
x = 1
y = 3
x = 2
y = 5
Volanie menom
def foo(x, y=3):
print("x =", x)
print("y =", y)
foo(y=1, x=4)
foo(x=5)
print("x",end=" ")
x = 4
y = 1
x = 5
y = 3
x
Procedúry
def p(a1, a2, a3):
if a2 >= 0.5:
print('Wow, that is bright!')
if a3 >= 0.5:
print("Wow, that is light!")
p(170, 0.1, 0.6)
Bill saw code like this...
Procedúry
def color_info(hue, saturation, luminosity):
if saturation >= 0.5:
print('Wow, that is bright!')
if luminosity >= 0.5:
print("Wow, that is light!")
color_info(hue=170, saturation=0.1, luminosity=0.6)
… and turn it into this. Be like Bill.
Rozsahy
★
★ ľ š
t = Turtle()
def move():
t.forward(100)
Rozsahy
★
if price > 10:
tmp = price
price *= 0.8
print("Discount from: {} to {} ".format(str(tmp), str(price)))
print("Print original price:", str(tmp)) #error
Rozsahy
var = "awesome"
def shadow():
var = "boring"
commend(var)
if True:
var = "interesting"
commend(var)
shadow()
commend(var)
Funkcie
Funkcie
★
★ ž ť š ž
Zdroj: https://www.math.rutgers.edu/~greenfie/summer_135/diary.html
Volanie funkcie
print(greet("students"))
def resolve_tax(salary):
if salary < 5000:
return 5
elif salary < 20000:
return 15
elif salary < 40000:
return 30
else:
return 50
If-elif
salary = 1000
if salary < 5000:
tax = 0.05
elif salary < 20000:
tax = 0.15
elif salary < 40000:
tax = 0.30
else:
tax = 0.50
Volanie funkcie
paid_tax = salary * resolve_tax(salary)
Volanie funkcie
def divisibility5(n):
return n % 5 == 0
a = divisibility5(1)
b = divisibility5(20)
c = divisibility5(4)
if(divisibility5(5)):
#...
a = False
b = True
c = False
Vstavané funkcie
★ print()
★ ž
○ ť
★ min()
★ max()
Math
★ č
○ from math import *
★ ľ round(), ceil(), floor()
★ sin(), cos(),...
★ exp(), log(), sqrt(),
...
Debug
Úloha 1
★ č č
○
■
■
○
■
■
★ factorial(5) = 120
★ sum_of_numbers(100) = 5050
Úloha 2
● č
ľ č n
● divisor_count(18) = 6
■ 1,2,3,6,9,18
Úloha 3
● č č
č ž ť š
● č ž
●
○ is_prime(7) = True
○ is_prime(1) = False
○ is_prime(4) = False
Úloha 4
●
č ť ž ť č č ž
● n_primes(4) = 2 3 5 7
Úloha 5*
● čš
č ľ
● gcd(7,33) = 1
● gcd(5, 10)= 5
● gcd(42, 36)= 6
Úloha 6*
● š
č
● lcm(9,3) = 9
● lcm(360,42) = 2520
● š
č
● factorization(25) = “5*5”
● factorization(42) = “2*3*7”
Úloha 7*
●
● č ť
● Ď
○
○
Zbierka
Credits
Special thanks to all the people who made and released
these awesome resources for free:
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