Python Basics

In [1]:

    

listOfNumbers = [1, 2, 3, 4, 5, 6]

for number in listOfNumbers:
    print(number)
    if (number % 2 == 0):
        print("is even")
    else:
        print("is odd")
        
print "All done."


    

    




1
is odd
2
is even
3
is odd
4
is even
5
is odd
6
is even
All done.

In [2]:

    

import numpy as np

A = np.random.normal(25.0, 5.0, 10)
print A


    

    




[ 27.35419908  25.67049043  25.50538002  30.82249618  24.89535506
  27.37209996  21.39864835  20.5220847   24.05849852  26.26014998]

In [3]:

    

x = [1, 2, 3, 4, 5, 6]
print(len(x))


    

    




6

In [4]:

    

x[:3]


    

    
Out[4]:





[1, 2, 3]

In [5]:

    

x[3:]


    

    
Out[5]:





[4, 5, 6]

In [6]:

    

x[-2:]


    

    
Out[6]:





[5, 6]

In [7]:

    

x.extend([7,8])
x


    

    
Out[7]:





[1, 2, 3, 4, 5, 6, 7, 8]

In [8]:

    

x.append(9)
x


    

    
Out[8]:





[1, 2, 3, 4, 5, 6, 7, 8, 9]

In [9]:

    

y = [10, 11, 12]
listOfLists = [x, y]
listOfLists


    

    
Out[9]:





[[1, 2, 3, 4, 5, 6, 7, 8, 9], [10, 11, 12]]

In [10]:

    

y[1]


    

    
Out[10]:





11

In [11]:

    

z = [3, 2, 1]
z.sort()
z


    

    
Out[11]:





[1, 2, 3]

In [12]:

    

z.sort(reverse=True)
z


    

    
Out[12]:





[3, 2, 1]

In [13]:

    

#Tuples are just immutable lists. Use () instead of []
x = (1, 2, 3)
len(x)


    

    
Out[13]:





3

In [14]:

    

y = (4, 5, 6)
y[2]


    

    
Out[14]:





6

In [15]:

    

listOfTuples = [x, y]
listOfTuples


    

    
Out[15]:





[(1, 2, 3), (4, 5, 6)]

In [16]:

    

(age, income) = "32,120000".split(',')
print(age)
print(income)


    

    




32
120000

In [17]:

    

# Like a map or hash table in other languages
captains = {}
captains["Enterprise"] = "Kirk"
captains["Enterprise D"] = "Picard"
captains["Deep Space Nine"] = "Sisko"
captains["Voyager"] = "Janeway"

print(captains["Voyager"])


    

    




Janeway

In [18]:

    

print(captains.get("Enterprise"))


    

    




Kirk

In [19]:

    

print(captains.get("NX-01"))


    

    




None

In [20]:

    

for ship in captains:
    print(ship + ": " + captains[ship])


    

    




Voyager: Janeway
Deep Space Nine: Sisko
Enterprise D: Picard
Enterprise: Kirk

In [21]:

    

def SquareIt(x):
    return x * x

print(SquareIt(2))


    

    




4

In [22]:

    

#You can pass functions around as parameters
def DoSomething(f, x):
    return f(x)

print(DoSomething(SquareIt, 3))


    

    




9

In [23]:

    

#Lambda functions let you inline simple functions
print(DoSomething(lambda x: x * x * x, 3))


    

    




27

In [25]:

    

print(1 == 3)


    

    




False

In [26]:

    

print(True or False)


    

    




True

In [27]:

    

print(1 is 3)


    

    




False

In [28]:

    

if 1 is 3:
    print("How did that happen?")
elif 1 > 3:
    print("Yikes")
else:
    print("All is well with the world")


    

    




All is well with the world

In [29]:

    

for x in range(10):
    print(x)


    

    




0
1
2
3
4
5
6
7
8
9

In [30]:

    

for x in range(10):
    if (x is 1):
        continue
    if (x > 5):
        break
    print(x)


    

    




0
2
3
4
5

In [31]:

    

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


    

    




0
1
2
3
4
5
6
7
8
9

In [ ]: