python for quantum (datascience) by maaz

Python: Quick Reference ¶

---

• Variables
• Arithmetic operators
• Objects
• Size of an object
• Loops
• Conditionals
• Logical and Boolean operators
• Double list
• List operations
• Functions
• Random number

---

Variables 

In [ ]:

number = 5 # integer

real = -3.4 # float

​

name = 'Asja' # string

surname = "Sarkana" # string

​

boolean1 = True # Boolean 

boolean1 = False # Boolean 

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Arithmetic operators 

Basic operators 

In [ ]:

a = 13

b = 5

print("a =",a)

print("b =",b)

print()

​

# basics operators

print("a + b =",a+b)

print("a - b =",a-b)

print("a * b =",a*b)

print("a / b =",a/b)

Integer division and modulus operators 

In [ ]:

a = 13

b = 5

print("a =",a)

print("b =",b)

print()

​

# integer division

print("a//b =",a//b)

​

# modulus operator

print("a mod b =",a % b)

Exponent operator

number**exponent

In [ ]:

b = 5

print("b =",b)

print()

​

print("b*b =",b**2)

print("b*b*b =",b**3)

print("sqrt(b)=",b**0.5)

---

Objects 

Lists 

In [ ]:

# list

mylist = [10,8,6,4,2] 

​

print(mylist)

Tuple 

In [ ]:

# tuple

mytuple=(1,4,5,'Asja') 

​

print(mytuple)

Dictionary 

In [ ]:

# dictionary

mydictionary = {

    'name' : "Asja",

    'surname':'Sarkane',

    'age': 23

}

​

print(mydictionary)

​

print(mydictionary['surname'])

List of the other objects or variables 

In [ ]:

# list of the other objects or variables

list_of_other_objects =[

    mylist,

    mytuple,

    3,

    "Asja",

    mydictionary

]

​

print(list_of_other_objects)

---

Size of an object 

We use the method "len()" that takes an object as the input.

In [ ]:

# length of a string

print(len("Asja Sarkane"))

​

# size of a list

print(len([1,2,3,4]))

​

# size of a dictionary

mydictionary = { 'name' : "Asja", 'surname':'Sarkane', 'age': 23}

print(len(mydictionary))

---

Loops 

While-loop 

In [ ]:

i = 10

while i>0: # while condition(s):

    print(i)

    i = i - 1   

For-loop 

In [ ]:

for i in range(10): # i is in [0,1,...,9]

    print(i)

In [ ]:

for i in range(-5,6): # i is in [-5,-4,...,0,...,4,5]

    print(i)

In [ ]:

for i in range(0,23,4): # i is in [0,4,8,12,16,20]

    print(i)

In [ ]:

for i in [3,8,-5,11]: 

    print(i)

In [ ]:

for i in "Sarkane":

    print(i)

In [ ]:

# dictionary

mydictionary = {

    'name' : "Asja",

    'surname':'Sarkane',

    'age': 23,

}

​

for key in mydictionary:

    print("key is",key,"and its value is",mydictionary[key])

---

Conditionals 

In [ ]:

for a in range(4,7):

    # if condition(s)

    if a<5: 

        print(a,"is less than 5")

    # elif conditions(s)

    elif a==5: 

        print(a,"is equal to 5")

    # else

    else:

        print(a,"is greater than 5")

---

Logical and Boolean operators

Logical operator "and"

In [ ]:

# Logical operator "and"

i = -3

j = 4

if i<0 and j > 0:  

    print(i,"is negative AND",j,"is positive")

Logical operator "or"

In [ ]:

# Logical operator "or"

i = -2

j = 2

if i==2 or j == 2:  

    print("i OR j is 2: (",i,",",j,")")

Logical operator "not" 

In [ ]:

# Logical operator "not"

i = 3

if not (i==2):

    print(i,"is NOT equal to 2")

Operator "equal to" 

In [ ]:

# Operator "equal to"

i = -1

if i == -1:

    print(i,"is EQUAL TO -1")

Operator "not equal to" 

In [ ]:

# Operator "not equal to"

i = 4

if i != 3:

    print(i,"is NOT EQUAL TO 3")

Operator "less than or equal to" 

In [ ]:

# Operator "not equal to"

i = 2

if i <= 5:

    print(i,"is LESS THAN OR EQUAL TO 5")

Operator "greater than or equal to" 

In [ ]:

# Operator "not equal to"

i = 5

if i >= 1:

    print(i,"is GREATER THAN OR EQUAL TO 3")

---

Double list 

In [ ]:

A =[

    [1,2,3],

    [-2,-4,-6],

    [3,6,9]

]

​

# print all

print(A)

print()

​

# print list by list

for list in A:

    print(list)

---

List operations

Concatenation of two lists 

In [ ]:

list1 = [1,2,3]

list2 = [4,5,6]

​

#concatenation of two lists

​

list3 = list1 + list2

print(list3)

​

list4 = list2 + list1

print(list4)

Appending a new element 

In [ ]:

list = [0,1,2]

​

list.append(3)

print(list)

​

list = list + [4]

print(list)

---

Functions

In [ ]:

def summation_of_integers(n):

    summation = 0

    for integer in range(n+1):

        summation = summation + integer

    return summation

​

print(summation_of_integers(10))

print(summation_of_integers(20))

---

Random number

We can use method "randrange()".

In [ ]:

from random import randrange

​

print(randrange(10),"is picked randomly between 0 and 9")

print(randrange(-9,10),"is picked randomly between -9 and 9")

​

print(randrange(0,20,3),"is picked randomly from the list [0,3,6,9,12,15,18]")