In [1]:
five = 5
In [2]:
print(five)
5
In [3]:
five = 3
In [4]:
## do I know how many times I want to iterate?
import random
count = 1
while random.random() < 0.5:
    count += 1
print(count)
1
In [5]:
## Do I have a list that I want to iterate over?
# (if no)
for i in range(10):
    print(i)
0
1
2
3
4
5
6
7
8
9
In [6]:
## Do I want to create a new list? 
# (if no)

my_list = [3, "hi", True, 2.1]
for value in my_list:
    print(value)
3
hi
True
2.1
In [7]:
## if yes
numbers = [1, 8, 7, 12]
[ x for x in numbers ]  # "list comprehension"
Out[7]:
[1, 8, 7, 12]
In [8]:
one_more = [ x + 1 for x in numbers ]
print(one_more)
[2, 9, 8, 13]
In [9]:
negative_small = [ -x for x in numbers if x < 8 ]
print(negative_small)
[-1, -7]
In [10]:
long_number_list = [0.342034234, 3.2345232, 5.3029423]
[ "{}".format(x) for x in long_number_list ]
Out[10]:
['0.342034234', '3.2345232', '5.3029423']
In [11]:
[ "{} {}".format(x, x + 2) for x in long_number_list ]
Out[11]:
['0.342034234 2.3420342339999998',
 '3.2345232 5.2345232',
 '5.3029423 7.3029423']
In [12]:
[ "{:.3f}".format(x) for x in long_number_list ]
Out[12]:
['0.342', '3.235', '5.303']
In [13]:
"{:b}".format(5)
Out[13]:
'101'
In [14]:
## Expectation of uniform from 0-99
expectation = 0
for x in range(100):
    expectation += x * (1/100)
print(expectation)
49.5
In [18]:
## Expectation of x squared
zero_to_99 = list(range(100))

squared_values = [ x * x for x in zero_to_99 ]
print(squared_values)
expectation = 0
for x_squared in squared_values:
    expectation += x_squared * (1/100)
print(expectation)
[0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225, 256, 289, 324, 361, 400, 441, 484, 529, 576, 625, 676, 729, 784, 841, 900, 961, 1024, 1089, 1156, 1225, 1296, 1369, 1444, 1521, 1600, 1681, 1764, 1849, 1936, 2025, 2116, 2209, 2304, 2401, 2500, 2601, 2704, 2809, 2916, 3025, 3136, 3249, 3364, 3481, 3600, 3721, 3844, 3969, 4096, 4225, 4356, 4489, 4624, 4761, 4900, 5041, 5184, 5329, 5476, 5625, 5776, 5929, 6084, 6241, 6400, 6561, 6724, 6889, 7056, 7225, 7396, 7569, 7744, 7921, 8100, 8281, 8464, 8649, 8836, 9025, 9216, 9409, 9604, 9801]
3283.5000000000005
In [16]:
list
Out[16]:
list
In [ ]: