(1) python, pip installert

(2) Variabler
Python er object oriented, "objects" kan innholde fields (attributes) eller procedyrer (methods)
Man trenger ikke å deklarere variabler og variabel typer

Ex.
my_int = 1
print(my_int)

my_float = 1.5
print(my_float)

my_string = "hi!"
print(my_string)

my_list = [1, 2, 3]
print(my_list)
print(my_list[1])

print(list("my name is Eric and Eric is my name".split()))
['my', 'name', 'is', 'Eric', 'and', 'Eric', 'is', 'my', 'name']
print(set("my name is Eric or Eric is my name".split()))
set(['and', 'is', 'my', 'name', 'Eric'])


liste er ordna, kan ha dublettar
sett er alfabetisk ordna, du kan ikkje ha dublettar

("Hei, %s!" % names)

%s betyr: bruk streng-variebelen som kjem etterpå


a = 2
a = a + 1
a += 1


(3) String formattering
names = "Trond og Lene"
print("Hei, %s!" % names)

name = Chiara
age = 32
print("I dag blir %s %d år gammel." % (name, age))


(4) Operations
+, -, *, /, %, **
a = 5
b = a % 2
print(b)
c = a ** 3
print(c)

% = modulo (gir rest av divisoren)


(5) Andre operatører
antall elementer i lista:
len(my_list)
name = "Chiara"
print(len(name))
6

my_list.append(4)

my_string.startswith("h")

my_string.endswith("!")

my_sentence = "Hei Lene og Trond"

my_string.split(" ")

m = ["asdf", "bsdf", "csf"]
m.append("ddfg")
print(m)
['asdf', 'bsdf', 'csf', 'ddfg']
print(m[1].startswith("a"))
False
print(m[1].endswith("a"))
False
print(m[1].endswith("f"))
True


(6) Conditions
if (condition):
    code to do something
elif (another condition):
    code to do something else
else:
    code to do another thing

Ex.
names = "Lene og Trond"
if (names == "Lene"):
    print("Hei Lene!")
elif (names == "Trond"):
    print("Hei Trond!")
else:
    print("Hei Lene og Trond“)

! betyr if false
if (names != "Lene"):
    print("Hei Lene!")

list = ["Lene", "Trond", "Chiara"]
if "Lene" in list:
    print("Hei Lene")



(7) Loops
For-loop
# Prints out 1,2,3
my_list = [1, 2, 3]
for number in my_list:
    print(number)

- range function (zero-based)
# Prints out 0,1,2,3,4
for x in range(5):
    print(x)

# Prints out 3,4,5
for x in range(3, 6):
    print(x)

# Prints out 3,5,7
for x in range(3, 8, 2):
    print(x)


import random
for x in range(10):
  print random.randint(1,101)
  print random.uniform(1.5, 1.9)


While-loop
# Prints out 0,1,2,3
count = 0
while count < 4:
    print(count)
    count += 1

- break (exit loop) and continue (skip current block and go back to loop-statement)
# Prints out 0,1,2,3,4
count = 0
while True:
    print(count)
    count += 1
    if count >= 5:
        break

# Prints out only odd numbers - 1,3,5,7,9
for x in range(10):
    # Check if x is even
    if x % 2 == 0:
        continue
    print(x)


(8) Functions
def my_function():
    print("Hello from my function!")

my_function()

def my_function(f):
    print("Hello to %s from my function!" % (f))

namn = "Lene"
my_function(namn)

def sum_two_numbers(a, b):
    return a + b

x = sum_two_numbers(1,2)
print(x)
num1 = 1
num2 = 2
x = sum_two_numbers(num1, num2)
print(x)
x = sum_two_numbers(num1, num1)
print(x)


(9) Classes, think of them as templates to create objects
Version1:

class my_class:
    color = "red"

    def function(self):
        print("The color of this class is, %s!" % self.color)

my_object1 = my_class()
my_object2 = my_class()

my_object2.color = "green"

# Then print out both values
my_object1.function()
my_object2.function()

Version2:

class class_colors:
    global color1, color2, color3
    color1 = ["red", "rosa", "blue", "black"]
    color2 = "green"
    color3 = "blue"

    def function_for(self):
        for item in color1:
            print("The color of this class is, %s!" % item)

my_object1 = class_colors()
my_object2 = class_colors()

my_object2.color3 = "green"

print((my_object1).function_for())
print((my_object1).function_for())

The color of this class is, red!
The color of this class is, rosa!
The color of this class is, blue!
The color of this class is, black!
None
The color of this class is, red!
The color of this class is, rosa!
The color of this class is, blue!
The color of this class is, black!
None

get None because print((my_object1).function_for()) prints what is returned in function_for() --> None