Python for erettsegi

https://www.python.org

test exam

in Hungarian

in English

example

in Hungarian

in English

File read

f = open('filename.txt','r')
content = f.read()
f.close()

File write

f = open('filename.txt', 'w')
f.write(content)
f.close()

Array

array = [0,[8,9],2,3,4,5]
print(array[0])
print(array[1][1])

content = 'hello\nworld'
print(content)
content = content.split('\n')
print(content[1])
print(array)
array.append(101)
print(array)

If statement

x = True
y = False
if (x):
	print('x is True')
if (not y):
	print('y is False')
if (y == False):
	print('y is False')
elif (x):
	print('x and y are True')
else:
	print('y is True but x is not')
if (x == True and y == True):
	print('x and y are True')

For

array = [5,4,3,2,1]
for i in range(len(array)):
	print(array[i])
for element in array:
	print(element)

While

i = 0
while(i < 10):
	print(i)
	i+=1

Input

s = input()
print(s)
s = s.split(" ")
print(s[0])

Function

def hello(name):
	print('Hello '+name)
hello('World')

Change variable type

v = "8"
print(v + v)

v = int(v)
print(v + v)

v = str(v)
print(v + v)

v = "3.5"
v = float(v)
print(v * 2)

Random number

from random import randint
a = 0
b = 10
print(randint(a, b))

Exchange variable

a = 1
b = 0
print(a)
a,b = b,a
print(a)

Sorting

numbers = [5, 2, 3, 1, 4]
numbers = sorted(numbers)
print(numbers)

numbers = sorted(numbers, reverse=True)
print(numbers)

def test(a):
	return a[0]

numbers = [[5,'A'], [2,'B'], [3,'C'], [1,'D'], [4,'E']]
numbers = sorted(numbers, key=test, reverse=True)
print(numbers)

Arithmetic Operators

Operator	Description	Example
+ Addition	Adds values on either side of the operator.	a + b = 30
- Subtraction	Subtracts right hand operand from left hand operand.	a – b = -10
* Multiplication	Multiplies values on either side of the operator	a * b = 200
/ Division	Divides left hand operand by right hand operand	b / a = 2
% Modulus	Divides left hand operand by right hand operand and returns remainder	b % a = 0
** Exponent	Performs exponential (power) calculation on operators	a**b =10 to the power 20
//	Floor Division - The division of operands where the result is the quotient in which the digits after the decimal point are removed. But if one of the operands is negative, the result is floored, i.e., rounded away from zero (towards negative infinity) −	9//2 = 4 and 9.0//2.0 = 4.0, -11//3 = -4, -11.0//3 = -4.0

Comparison Operators

Operator	Description	Example
==	If the values of two operands are equal, then the condition becomes true.	(a == b) is not true.
!=	If values of two operands are not equal, then condition becomes true.	(a != b) is true.
<>	If values of two operands are not equal, then condition becomes true.	(a <> b) is true. This is similar to != operator.
>	If the value of left operand is greater than the value of right operand, then condition becomes true.	(a > b) is not true.
<	If the value of left operand is less than the value of right operand, then condition becomes true.	(a < b) is true.
>=	If the value of left operand is greater than or equal to the value of right operand, then condition becomes true.	(a >= b) is not true.
<=	If the value of left operand is less than or equal to the value of right operand, then condition becomes true.	(a <= b) is true.

Assignment Operators

Operator	Description	Example
=	Assigns values from right side operands to left side operand	c = a + b assigns value of a + b into c
+= Add AND	It adds right operand to the left operand and assign the result to left operand	c += a is equivalent to c = c + a
-= Subtract AND	It subtracts right operand from the left operand and assign the result to left operand	c -= a is equivalent to c = c - a
*= Multiply AND	It multiplies right operand with the left operand and assign the result to left operand	c *= a is equivalent to c = c * a
/= Divide AND	It divides left operand with the right operand and assign the result to left operand	c /= a is equivalent to c = c / ac /= a is equivalent to c = c / a
%= Modulus AND	It takes modulus using two operands and assign the result to left operand	c %= a is equivalent to c = c % a
**= Exponent AND	Performs exponential (power) calculation on operators and assign value to the left operand	c **= a is equivalent to c = c ** a
//= Floor Division	It performs floor division on operators and assign value to the left operand	c //= a is equivalent to c = c // a