#!/usr/bin/env python
# coding: utf-8

# # 9 Dictionaries
# <a href="https://colab.research.google.com/github/rambasnet/FDSPython-Notebooks/blob/master/Ch09-1-Dictionaries.ipynb" target="_parent"><img src="https://colab.research.google.com/assets/colab-badge.svg" alt="Open In Colab"/></a>
# 
# http://openbookproject.net/thinkcs/python/english3e/dictionaries.html
# 
# ## Topics
# - dictionary data types
# - create and use dictionary
# - dictionary methods and operations
# - dictionary applications and problems
# 
# 
# ## 9.1 Dictionary
# - another compound type/container like lists and tuples
# - very useful data structure/container that can store data as lookup table 
# - Python's mapping type similar to `map` container, or associative arrays in C++ and other languages
# - dictionaries maps keys (immutable type) to values of any type (heterogeneous)
# - Python uses complex hash algorithm to index key for fast access (Worst case "Big-Oh": $O(1)$)
#     - as a result the ordering is not maintained
# - starting from verion 3.7, python dict remembers the oderes of the elements inserted

# ## 9.2 Creating dictionary objects

# In[1]:


eng2sp = {} # or
eng2sp1 = dict()


# In[2]:


print(eng2sp, eng2sp1)


# In[3]:


eng2sp["One"] = "uno"
eng2sp["two"] = "dos"
eng2sp["three"] = "tres"
eng2sp[4] = "quatro"
eng2sp["five"] = "sinco"


# In[4]:


eng2sp


# In[5]:


key = 'Five'
eng2sp[key] = 'Sinco'


# In[6]:


print(eng2sp)


# In[7]:


print(eng2sp['One'])


# In[9]:


symbolNames = {'*':'asterick', '+':"plus", '-': 'minus'}


# In[10]:


print(eng2sp, symbolNames)


# In[11]:


dict1 ={'one': 'uno', 'two': 'dos', 'three': 'tres', '4': 'quatro', 'five': 'sinco'}


# In[12]:


dict1


# ## 9.3 Accessing values
# - use index operator ['key'] 
# - dict is mutable

# In[14]:


one = 'One'


# In[15]:


eng2sp[one]


# In[16]:


eng2sp


# In[17]:


eng2sp['ten'] = 'diez'
print(eng2sp['ten'])


# In[18]:


eng2sp['One'] = 'Uno'


# In[19]:


eng2sp


# In[20]:


eng2sp['One'] = ['uno']


# In[21]:


eng2sp['One'].append('Uno')


# In[25]:


eng2sp['One'].insert(0, 'UNO')


# In[26]:


print(eng2sp)


# In[28]:


adict = {1: ['uno', 'one'], 2:('two', 'dos'), 3:{'three':'tres'}}


# In[35]:


print(adict[2][1])


# In[33]:


# How do you access tres in adict?
print(adict[3]['three'])


# ## 9.4 Dictionary methods

# In[36]:


help(dict)


# In[37]:


for k in eng2sp.keys(): # the order of the keys is not defined
    print("key {} maps to value {}".format(k, eng2sp[k]))


# In[38]:


print(list(eng2sp.keys()))


# In[39]:


print(list(eng2sp.values()))


# In[40]:


# iterate over keys
for k in eng2sp:
    print('key = {} value = {}'.format(k, eng2sp.get(k)))


# In[43]:


print(eng2sp.get('asdfsf'))


# In[49]:


print(eng2sp.get("Ondfe"))


# In[50]:


# iterate over values
for val in eng2sp.values():
    print("value = ", val)


# In[51]:


values = list(eng2sp.values())


# In[52]:


values


# In[53]:


items = list(eng2sp.items())


# In[54]:


print(items)


# In[ ]:


dict2 = dict(items)
print(dict2)


# In[ ]:


for k, v in eng2sp.items():
    print('{} -> {}'.format(k, v))


# In[ ]:


print(eng2sp.popitem())
print(eng2sp)


# ## 9.5 Checking keys
# - in and not in operators can be used to check if some keys exist in a given dictionary
# - knowing if key exists helps automatically create dictionaries and access corresponding values

# In[ ]:


"One" in eng2sp


# In[ ]:


"Ten" in eng2sp


# In[ ]:


"twenty" not in eng2sp


# ## 9.6 Copying dictionary objects
# - shallow copy vs deep copy

# In[ ]:


import copy
digits = {1: 'one', 2: 'two', 3: ['three', 'Three', 'THREE']}
digits1 = digits # creates an alias
digits2 = digits.copy() # shallow copy
digits3 = copy.deepcopy(digits) # deep copy


# ### [visualize in pythontutor.com](https://goo.gl/XmvYkB)

# In[ ]:


from IPython.display import IFrame
src = '''
http://pythontutor.com/iframe-embed.html#code=import%20copy%0Adigits%20%3D%20%7B1%3A%20'one',%202%3A%20'two',%203%3A%20%5B'three',%20'Three',%20'THREE'%5D%7D%0Adigits1%20%3D%20digits%20%23%20creates%20an%20alias%0Adigits2%20%3D%20digits.copy%28%29%20%23%20shallow%20copy%0Adigits3%20%3D%20copy.deepcopy%28digits%29%20%23%20deep%20copy&codeDivHeight=400&codeDivWidth=350&cumulative=false&curInstr=0&heapPrimitives=false&origin=opt-frontend.js&py=3&rawInputLstJSON=%5B%5D&textReferences=false
'''
IFrame(src, width=900, height=600)


# ## 9.7 Passing dictionaries to functions
# - dict is a mutable type
# - therefore, dict objects are passed by reference

# In[ ]:


# find the histogram (frequency of each unique character) in a word
def histogram(word, hist):
    for c in word:
        c = c.lower()
        if c in hist:
            hist[c] += 1
        else:
            hist[c] = 1


# In[ ]:


h = {}
histogram('Mississippim', h)
for k, v in h.items():
    print(k, v)


# ## 9.8 Returning dict from functions
# - dict objects can be returned from functions

# In[ ]:


def getHist(word):# = "Mississippi"
    h = {}
    for c in word:
        if c in h:
            h[c] += 1
        else:
            h[c] = 1
    return h


# In[ ]:


hist = getHist('Mississippi')
print(hist)
if 'M' in hist:
    print('M is in histogram')


# ## 9.9 Exercises

# 1. Count and print letter frequency in a given word. Hint: use get method

# 2. Write a program that reads some text data and prints a frequency table of the letters in alphabetical order. Case should be ignored. A sample output of the program when the user enters the data "ThiS is String with Upper and lower case Letters", would look this:
# <pre>
# a  2
# c  1
# d  1
# e  5
# g  1
# h  2
# i  4
# l  2
# n  2
# o  1
# p  2
# r  4
# s  5
# t  5
# u  1
# w  2
# </pre>

# ## Kattis problems that can be solved using dict
# 1. I've Been Everywhere, Man -  https://open.kattis.com/problems/everywhere
# - Seven Wonders - https://open.kattis.com/problems/sevenwonders
# - ACM Contest Scoring - https://open.kattis.com/problems/acm
# - Stacking Cups - https://open.kattis.com/problems/cups
# - A New Alphabet - https://open.kattis.com/problems/anewalphabet
# - Words for Numbers - https://open.kattis.com/problems/wordsfornumbers
# - Babelfish - https://open.kattis.com/problems/babelfish
# - Popular Vote - https://open.kattis.com/problems/vote
# - Adding Words - https://open.kattis.com/problems/addingwords
# - Grandpa Bernie - https://open.kattis.com/problems/grandpabernie
# - Judging Troubles - https://open.kattis.com/problems/judging
# - Not Amused - https://open.kattis.com/problems/notamused
# - Engineering English - https://open.kattis.com/problems/engineeringenglish
# - Hardwood Species - https://open.kattis.com/problems/hardwoodspecies
# - Conformity - https://open.kattis.com/problems/conformity
# - Galactic Collegiate Programming Contest - https://open.kattis.com/problems/gcpc
# - Simplicity - https://open.kattis.com/problems/simplicity

# In[ ]: