1. Presented by Mirza Elahi 10/29/2018
PYTHON DATATYPES CPS 6195
Presented by Mirza Elahi
10/29/2018

2. Outline Python Datatypes Numbers List Tuple String Set Dictionary
Nested Dictionary
Arrays
Matrix
List Comprehension

3. Number Data Type 3 different class, int, float, complex Functions,
>>>5
int(-5.3)
>>>-5
float(2)
>>>2.0
complex(‘7+11j’)
>>>(7+11j)
print( )
>>>3.0
Functions,
type(), isinstance()
a = 1
b = 2.0
c = j
print(type(a))
print(type(b))
print(type(c))
print(isinstance(c, complex))

4. Number System Decimal, base 10 Binary, base 2 Hexadecimal, base 16
Octal, base 8
print(0b ) 107 print(0xFB + 0b10) 253 ( ) print(0o15) 13

5. Type Conversion Decimal (1.1 + 2.2) == 3.3 >>>False
print( )
>>>
from decimal import Decimal as D
print(D('1.1') + D('2.2’))
>>>3.3
Fractions
import fractions
print(fractions.Fraction(1.5))
>>>3/2
print(fractions.Fraction(1,3))
>>>1/3
print(fractions.Fraction('1.1’))
>>>11/10
from fractions import Fraction as F
print(F(1,3) + F(1,3))
>>>2/3

6. Mathematics math import math print(math.pi) 3.141592653589793
print(math.cos(math.pi))
-1.0
Rand
import random
print(random.random())
print(random.randrange(1, 10))
x = ['a', 'b', 'c', 'd', 'e']
print(random.choice(x))
random.shuffle(x)
print(x)

7. List List methods list.method() print(cps.count(2)) Create List
cps =[“utep”,[2,0,1,8],[‘z’]]
Access elements
print(cps[0][1])
print(cps[1][2])
print(cps[-1])
Slice list
cps = [1,3,9]
print(cps[:])
print(cps[1:2])
Add / change elements
cps[2:2] = [5, 7]
Remove elements
del cps[0:1]
List methods
list.method()
print(cps.count(2))

8. List Comprehension List comprehension Built in list functions
cps =[2 ** x for x in range(10)]
cps =[2 ** x for x in range(10) if x>5]
cps =[2 ** x for x in range(10) if x%2 == 1]
Built in list functions
cps =[]
For x in range(10):
cps.append(2 ** x)

9. Tuple Similar to a list but the elements in a tuple cannot be changed.
Used for heterogeneous datatypes, key for a dictionary, performance boost.
Create tuple
cps = (1, 2, 3)
cps = (2018, “utep”, 1.1)
cps = (“utep”,[2 3 5], (1,2,3))
cps = 1,2,3, “utep”
One element tuple
cps = (”utep",)
print(type(cps))

10. Access, Change & Delete Elements
Indexing
cps= ( ‘u’, ‘t’, ‘e’, ‘p’)
print(cps[0])
print(cps[-1])
print(cps[1:2])
n_cps = (“utep”,[1 2 3],(4 5 6))
print(n_cps[0][4])
Changing tuple
n_cps[2][0] = 7
print(n_cps)
print((1, 2, 3) + (4, 5, 6))
print((”utep",) * 3)
Deleting Tuple
del cps
Tuple Methods
cps= (‘d’,’e’,’l’,’e’, ’t’, ’e’,)
print(cps.count(‘e'))
print(cps.index(‘l'))

11. Other Operations Membership test using ‘in’ cps= ( ‘u’, ‘t’, ‘e’, ‘p’)
print(‘u’ in cps)
print(‘a’ in cps)
Iteration
for program in (‘Math’,’CPS'): print(”Utep",program)

12. String String is sequence of characters.
Characters are encoded with 0’s and 1’s by the computer.
Python uses Unicode.
Create String
cps = ‘Utep’
cps = “Utep”
cps = ’’’Utep’’’
cps = “““Hello, welcome
to the CPS program”””
Indexing, Slicing
cps = ‘cps2018' print('cps = ', cps) print('cps[0] = ', cps[0]) print('cps[-1] = ', cps[-1]) print('cps[1:5] = ', cps[1:5]) print('cps[2:-2] = ', cps[2:- 2])

13. Operations cps = ‘Utep2018’ cps[-1] = ‘7’ cps = ‘Welcome’ del cps[1]
Elements of string cannot be changed but can be reassigned to the same name.
cps = ‘Utep2018’
cps[-1] = ‘7’
cps = ‘Welcome’
del cps[1]
del cps
Membership Test using ‘in’
‘u’ in ‘utep’
‘t’ not in ‘utep’
Concatenation
cps1 = ‘Utep’
cps2 = ‘2018’
print(‘cps1+cps2=’, cps1 + cps2)
Print(‘cps1 * 3=’, cps1*3)
Iteration
count = 0
for letter in ‘utep cps':
if(letter == ‘p'):
count += 1
print(count,'letters found')

14. More Operations Built in functions cps = ‘utep'
list_enumerate = list(enumerate(cps))
print('list(enumerate(cps) = ', list_enumerate)
print('len(cps) = ', len(cps))

15. String Formatting He said, "What's there?" # using triple quotes
print('''He said, "What's there?"''')
# escaping single quotes
print('He said, "What\'s there?"')
# escaping double quotes
print("He said, \"What's there?\"")

16. Set Set is an unordered collection of items.
Set is mutable, meaning items can be added or removed.
Mathematical operations like union, intersection, symmetric difference can be carried out.
Create Set
cps= {6, 1, 9, 5}
cps = {1.0, “Utep”, (1, 2, 3)}
cps= set([1,2,3,2])
print(cps)
*no duplicates
Empty Set
a = {}
a = set()
print(type(a))

17. Change & Remove Elements
cps = {0,1}
cps.add(2)
cps.update([2,3,4])
cps.update([4,5],{1,6,9})
print(cps)
{0,1,2,3,4,5,6,9}
Remove Elements
cps = {1,3,5,7,9}
cps.discard(3)
cps.remove(7)
print(cps)
{1,5,9}
*remove(8) will cause an error.
cps = set("HelloWorld") print(cps.pop())
>>>W print(cps.clear())
>>>None

18. Set Operations Union A = {1, 2, 3, 4, 5} B = {4, 5, 6, 7, 8}
print(A | B)
A.union(B)
B.union(A)
>>>{1,2,3,4,5,6,7,8}
Intersection
Print(A & B)
A.intersection(B)
B.intersection(A)
>>>{4,5}
Difference or Only
Print(A – B)
A.difference(B)
>>>{1,2,3}
Print(B - A)
B.difference(A)
>>>{6,7,8}
Symmetric Difference
print(A ^ B)
A.symmetric_difference(B)
B.symmetric_difference(A)
>>> {1, 2, 3, 6, 7, 8}

19. Set Methods Set Membership Test cps = set(“Utep”) Print(‘U’ in cps)
>>>True
Print(‘p’ not in cps)
>>>False

20. Frozenset Immutable sets, meaning elements cannot be changed.
Can be used as dictionary keys unlike sets.
A = frozenset([1, 2, 3, 4])
B = frozenset([3, 4, 5, 6])
A.isdisjoint(B)
>>>False
A.difference(B)
>>>frozenset({1,2})

21. Q&A

22. Quiz 1. Can you change items in tuple? Yes or No.
cps_t = (1,2,3,[9,8])
cps_t[1] = 7
(element cannot be changed)
cps_t[3][0] = 7
(item of mutable element can be changed)

23. Quiz
2. Can you change the elements of a string? Yes or No. >>> cps = 'programiz’ >>> cps[5] = ‘a’ ... TypeError: 'str' object does not support item assignment >>> cps = 'Python’ >>> cps 'Python'
3. Can we access index using any range or decimal number? Yes or No. >>> cps[15] ... IndexError: string index out of range integer >>> cps[1.5] ... TypeError: string indices must be integers

24. Quiz
4. Can sets produce duplicates? Yes or no. >>>cps_set= {1,2,3,4,3,2} >>>print(cps_set) {1, 2, 3, 4} # set do not have duplicates >>>cps_set = {1, 2, [3, 4]} TypeError: unhashable type: 'list' # set cannot have mutable items # here [3, 4] is a mutable list # this will cause an error.
5. Can you remove elements not present in a set?
cps = {1,3,4}
cps.remove(2)
Error
*discard(2) is fine.

25. Examples
#add two matrices
X = [[12,7,3],
[4 ,5,6],
[7 ,8,9]]
Y = [[5,8,1],
[6,7,3],
[4,5,9]]
result = [[0,0,0],
[0,0,0],
[0,0,0]]
#iterate through rows for i in range(len(X)): #iterate through columns for j in range(len(X[0])): result[i][j] = X[i][j]+Y[i][j] for r in result: print(r)

26. Examples
# Program to sort alphabetically the words form a string provided by the user
# change this value for a different result
my_str = "Hello this Is an Example With cased letters"
# uncomment to take input from the user
#my_str = input("Enter a string: ")
# breakdown the string into a list of words
words = my_str.split()
# sort the list
words.sort()
print("The sorted words are:")
for word in words:
print(word)
The sorted words are:
Example
Hello Is
With an
cased
letters
this