# Execute this cell to define this variable
# Either click Cell => Run from the menu or type
# ctrl-Enter to execute. See the Help menu for lots
# of useful tips. Help => IPython Help and
# Help => Keyboard Shortcuts are especially
# useful.

message = "I want to mine the social web!"

# The variable 'message is defined here. Execute this cell to see for yourself
print message

# The variable 'message' is defined here, but we'll delete it
# after displaying it to illustrate an important point...
print message
del message

# The variable message is no longer defined in this cell or two cells 
# above anymore. Try executing this cell or that cell to see for yourself.
print message

# Try typing in some code of your own!

an_integer = 23
print an_integer, type(an_integer)
print

a_float = 23.0
print a_float, type(a_float)
print

a_string = "string"
print a_string, type(a_string)
print

a_list = [1,2,3]
print a_list, type(a_list)
print a_list[0] # access the first item
print

a_dict = {'a' : 1, 'b' : 2, 'c' : 3}
print a_dict, type(a_dict)
print a_dict['a'] # access the item with key 'a'

contacts = [
    {
      'name'      : 'Bob',
      'age'       : 23,
      'married'   : False,
      'height'    : 1.8, # meters
      'languages' : ['English', 'Spanish'],
      'address'   : '123 Maple St.',
      'phone'     : '(555) 555-5555'
    },
    
    {'name'      : 'Sally',
     'age'       : 26,
     'married'   : True,
     'height'    : 1.5, # meters
     'languages' : ['English'],
     'address'   : '456 Elm St.',
     'phone'     : '(555) 555-1234'
    }              
]

for contact in contacts:
    print "Name:", contact['name']
    print "Married:", contact['married']
    print

import json

print contacts
print type(contacts) # list

# json.dumps pronounced (dumps stands for "dump string") takes a Python data structure
# that is serializable to JSON and dumps it as a string
jsonified_contacts = json.dumps(contacts, indent=2) # indent is used for pretty-printing

print type(jsonified_contacts) # str
print jsonified_contacts

a_tuple = (1,2,3)

an_int = (1) # You must include a trailing comma when only one item is in the tuple

a_tuple = (1,)

a_tuple = (1,2,3,) # Trailing commas are ok in tuples and lists 

none = None

print none == None   # True
print none == True   # False
print none == False  # False

print

# In general, you'll see the special 'is' operator used when comparing a value to 
# None, but most of the time, it works the same as '=='

print none is None  # True
print none is True  # False
print none is False # False

def square(x):
    return x*x

print square(2) # 4
print

# The default value for L is only created once and shared amongst
# calls

def f1(a, L=[]):
    L.append(a)
    return L

print f1(1) # [1]
print f1(2) # [1, 2]
print f1(3) # [1, 2, 3]
print

# Each call creates a new value for L

def f2(a, L=None):
    if L is None:
        L = []
    L.append(a)
    return L

print f2(1) # [1]
print f2(2) # [2]
print f2(3) # [3]

a_list = ['a', 'b', 'c', 'd', 'e', 'f', 'g']

print a_list[0]     # a
print a_list[0:2]   # ['a', 'b']
print a_list[:2]    # Same as above. The starting index is implicitly 0
print a_list[3:]    # ['d', 'e', 'f', 'g'] Ending index is implicitly the length of the list
print a_list[-1]    # g Negative indices start at the end of the list
print a_list[-3:-1] # ['e', 'f'] Start at the end and work backwards. (The index after the colon is still excluded)
print a_list[-3:]   # ['e', 'f', 'g']  The last three items in the list
print a_list[:-4]   # ['a', 'b', 'c'] # Everything up to the last 4 items

a_string = 'abcdefg'

# String slicing works the very same way

print a_string[:-4] # abc

# One way to create a list containing 0..9:

a_list = []
for i in range(10):
    a_list.append(i)
print a_list    
    
# How to do it with a list comprehension

print [ i for i in range(10) ]


# But what about a nested loop like this one, which
# even contains a conditional expression in it:

a_list = []
for i in range(10):
    for j in range(10, 20):
        if i % 2 == 0:
            a_list.append(i)

print a_list

# You can achieve a nested list comprehension to 
# achieve the very same result. When written with readable
# indention like below, note the striking similarity to
# the equivalent code as presented above.

print [ i
        for i in range(10)
            for j in range(10, 20)
                if i % 2 == 0
      ]

# Literal syntax

a_dict = { 'a' : 1, 'b' : 2, 'c' : 3 }
print a_dict
print

# Using the dict constructor

a_dict = dict([('a', 1), ('b', 2), ('c', 3)])
print a_dict
print

# Dictionary comprehension syntax

a_dict = { k : v for (k,v) in [('a', 1), ('b', 2), ('c', 3)] }
print a_dict
print

# A more appropriate circumstance to use dictionary comprehension would 
# involve more complex computation

a_dict = { k : k*k for k in xrange(10) } # {0: 0, 1: 1, 2: 4, 3: 9, ..., 9: 81}
print a_dict

lst = ['a', 'b', 'c']

# You could opt to maintain a looping index...
i = 0
for item in lst:
    print i, item
    i += 1

# ...but the enumerate function spares you the trouble of maintaining a loop index
for i, item in enumerate(lst):
    print i, item

def f(a, b, c, d=None, e=None):
    print a, b, c, d, e

f(1, 2, 3)              # 1 2 3 None None
f(1, 3, 3, d=4)         # 1 2 3 4 None
f(1, 2, 3, d=4, e=5)    # 1 2 3 4 5

args = [1,2,3]
kwargs = {'d' : 4, 'e' : 5}

f(*args, **kwargs)      # 1 2 3 4 5

name1, name2 = "Bob", "Sally"

print "Hello, " + name1 + ". My name is " + name2

print "Hello, %s. My name is %s" % (name1, name2,)

print "Hello, {0}. My name is {1}".format(name1, name2)
print "Hello, {0}. My name is {1}".format(*[name1, name2])
names = [name1, name2]
print "Hello, {0}. My name is {1}".format(*names)


print "Hello, {you}. My name is {me}".format(you=name1, me=name2)
print "Hello, {you}. My name is {me}".format(**{'you' : name1, 'me' : name2})
names = {'you' : name1, 'me' : name2}
print "Hello, {you}. My name is {me}".format(**names)



import envoy # pip install envoy

# Run a command just as you would in a terminal on the virtual machine
r = envoy.run('ps aux | grep ipython') # show processes containing 'ipython'

# Print its standard output
print r.std_out

# Print its standard error
print r.std_err

# Print the working directory for the IPython Notebook server
print envoy.run('pwd').std_out

# Try some commands of your own...

%%bash

# Print the working directory
pwd 

# Display the date
date

# View the first 10 lines of a manual page for wget
man wget | head -10

# Download a webpage to /tmp/index.html
wget -O /tmp/foo.html http://ipython.org/notebook.html

# Search for 'ipython' in the webpage
grep ipython /tmp/foo.html

%%bash
ls ../
# Displays the status of the local repository
git status

# Execute "git pull" to perform an update

from IPython.display import IFrame
from IPython.core.display import display

# IPython Notebook can serve files relative to the location of
# the working notebook into inline frames. Prepend the path 
# with the 'files' prefix

static_content = 'files/resources/appc-pythontips/hello.txt'

display(IFrame(static_content, '100%', '600px'))

import os

# The absolute path to the shared folder on the VM
shared_folder="/vagrant"

# List the files in the shared folder
print os.listdir(shared_folder)
print

# How to read and display a snippet of the share/README.md file...
README = os.path.join(shared_folder, "README.md")
txt = open(README).read()
print txt[:200]

# Write out a file to the guest but notice that it is available on the host
# by checking the contents of your GitHub checkout
f = open(os.path.join(shared_folder, "Hello.txt"), "w")
f.write("Hello. This text is written on the guest but synchronized to the host by Vagrant")
f.close()

%%bash

tail -n 100 /var/log/kern.log

%%bash

ps -e -orss=,args= | sort -b -k1,1n | pr -TW$COLUMNS | tail -n 10