Three-Way Decisions

if, elif, else



In [52]:

    
t=0

if t > 60:
    print('its very hot')
elif t > 50:
    print('its hot')
elif t > 40:
    print('its warm')
else:
    print('its cool')









    



its cool



In [56]:

    
t=55

if t > 40:
    print('its very hot')
elif t > 50:
    print('its hot')
elif t > 60:
    print('its warm')
else:
    print('its cool')









    



its very hot

S be carefull!

while Loop



In [109]:

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

Queez

Once upon a time, there was king, who wanted lots of soldiers. So he commanded every couple in the country to have children, until their first dauter born. Then the family is banned from having any more child. What will be the ratio of boy/girls in this country?



In [112]:

    
from random import randint

children = 0
boy = 0

for i in range(10000):
    gender = randint(0,1) # boy=1, girl=0
    children += 1
    while gender != 0:
        boy += gender
        gender = randint(0,1)
        children += 1
print(boy/children)









    



0.5002498750624688

Control Statments

break, continue and pass



In [113]:

    
for i in range(10):
    print(i)
    if i == 5:
        break



In [116]:

    
for i in range(10):
    print(i)
    if i > 5:
        continue
    print("Hey")









    



0
Hey
1
Hey
2
Hey
3
Hey
4
Hey
5
Hey
6
7
8
9



In [122]:

    
def func():
    pass



In [123]:

    
func()

tuple



In [126]:

    
t = (0,1,'test')



In [129]:

    
print(t)
t[0]=1









    



(0, 1, 'test')






    



---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-129-98ddcef64135> in <module>()
      1 print(t)
----> 2 t[0]=1

TypeError: 'tuple' object does not support item assignment



In [131]:

    
(1,)









    Out[131]:





(1,)

Dictionaries

items get keys pop update values



In [138]:

    
d = {}
d['name'] = 'Hamed'
d['family name'] = 'Seyed-allaei'
d[0]=12
d['a']=''
print(d)
print(d['name'])
print(d[0])









    



{'family name': 'Seyed-allaei', 0: 12, 'name': 'Hamed', 'a': ''}
Hamed
12



In [140]:

    
for i,j in d.items():
    print(i,j)









    



family name Seyed-allaei
0 12
name Hamed
a

set

in, not in, len(), ==, !=, <=, <, |, &, -, ^



In [145]:

    
a = set(['c', 'a','b','b'])
b = set(['c', 'd','e'])
print(a,b)









    



{'a', 'c', 'b'} {'d', 'e', 'c'}



In [151]:

    
a | b









    Out[151]:





{'a', 'b', 'c', 'd', 'e'}



In [153]:

    
a & b









    Out[153]:





{'c'}



In [155]:

    
a - b









    Out[155]:





{'a', 'b'}



In [157]:

    
b - a









    Out[157]:





{'d', 'e'}



In [158]:

    
a ^ b









    Out[158]:





{'a', 'b', 'd', 'e'}

List comprehention



In [161]:

    
l = []
for i in range(10):
    l.append(i*i)
print(l)









    



[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]



In [167]:

    
[i*i for i in range(10)]









    Out[167]:





[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]



In [169]:

    
{i:i**2 for i in range(10)}









    Out[169]:





{0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25, 6: 36, 7: 49, 8: 64, 9: 81}

Generators

next()



In [189]:

    
def myrange(n):
    i = 0
    while i < n:
        yield i
        yield i**2
        i+=1
        
x = myrange(10)
type(x)









    Out[189]:





generator



In [202]:

    
next(x)









    Out[202]:





6



In [203]:

    
[i for i in myrange(10)]









    Out[203]:





[0, 0, 1, 1, 2, 4, 3, 9, 4, 16, 5, 25, 6, 36, 7, 49, 8, 64, 9, 81]



In [ ]:

    
for i in myrange(10):
    print(i)

Fibonacci

This time as a generator.