Installing Python and GraphLab Create

Please follow the installation instructions here before getting started:

We have done

Installed Python
Started Ipython Notebook

Getting started with Python



In [1]:

    
print 'Hello World!'









    



Hello World!

Create some variables in Python



In [2]:

    
i = 4  #int



In [3]:

    
type(i)









    Out[3]:





int



In [4]:

    
f = 4.1  #float



In [5]:

    
type(f)









    Out[5]:





float



In [6]:

    
b = True  #boolean variable



In [7]:

    
s = "This is a string!"



In [8]:

    
print s









    



This is a string!

Advanced python types



In [9]:

    
l = [3,1,2]  #list



In [10]:

    
print l









    



[3, 1, 2]



In [11]:

    
d = {'foo':1, 'bar':2.3, 's':'my first dictionary'}  #dictionary



In [12]:

    
print d









    



{'s': 'my first dictionary', 'foo': 1, 'bar': 2.3}



In [13]:

    
print d['foo']  #element of a dictionary



In [14]:

    
n = None  #Python's null type



In [15]:

    
type(n)









    Out[15]:





NoneType

Advanced printing



In [16]:

    
print "Our float value is %s. Our int value is %s." % (f,i)  #Python is pretty good with strings









    



Our float value is 4.1. Our int value is 4.

Conditional statements in python



In [17]:

    
if i == 1 and f > 4:
    print "The value of i is 1 and f is greater than 4."
elif i > 4 or f > 4:
    print "i or f are both greater than 4."
else:
    print "both i and f are less than or equal to 4"









    



i or f are both greater than 4.

Conditional loops



In [18]:

    
print l









    



[3, 1, 2]



In [19]:

    
for e in l:
    print e

Note that in Python, we don't use {} or other markers to indicate the part of the loop that gets iterated. Instead, we just indent and align each of the iterated statements with spaces or tabs. (You can use as many as you want, as long as the lines are aligned.)



In [20]:

    
counter = 6
while counter < 10:
    print counter
    counter += 1

Creating functions in Python

Again, we don't use {}, but just indent the lines that are part of the function.



In [21]:

    
def add2(x):
    y = x + 2
    return y



In [22]:

    
i = 5



In [23]:

    
add2(i)









    Out[23]:





7

We can also define simple functions with lambdas:



In [24]:

    
square = lambda x: x*x



In [ ]: