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

# # Dictionary

# In[1]:


my_dict = {}
grades = {'Ana':'B', 'John':'A+', 'Denise':'A', 'Katy':'A'}


# In[2]:


grades['John']


# In[3]:


grades['sylvan']


# In[4]:


grades['Sylvan'] = 'A' # add an entry
grades['Sylvan']


# In[5]:


'John' in grades


# In[6]:


'Daniel' in grades


# In[7]:


del(grades['Ana'])


# In[8]:


grades


# In[10]:


grades.keys()


# In[11]:


grades.values()


# In[12]:


d = {4:{1:0}, (1,3):"twelve", 'const':[3.14,2.7,8.44]}
d


# ## Ví dụ - Analyze song lyrics

# In[14]:


def lyrics_to_frequencies(lyrics):
    myDict = {}
    for word in lyrics:
        if word in myDict:
            myDict[word] += 1
        else:
            myDict[word] = 1
    return myDict


# In[16]:


she_loves_you = ['she', 'loves', 'you', 'yeah', 'yeah', 'yeah',
'she', 'loves', 'you', 'yeah', 'yeah', 'yeah',
'she', 'loves', 'you', 'yeah', 'yeah', 'yeah',

'you', 'think', "you've", 'lost', 'your', 'love',
'well', 'i', 'saw', 'her', 'yesterday-yi-yay',
"it's", 'you', "she's", 'thinking', 'of',
'and', 'she', 'told', 'me', 'what', 'to', 'say-yi-yay',

'she', 'says', 'she', 'loves', 'you',
'and', 'you', 'know', 'that', "can't", 'be', 'bad',
'yes', 'she', 'loves', 'you',
'and', 'you', 'know', 'you', 'should', 'be', 'glad',

'she', 'said', 'you', 'hurt', 'her', 'so',
'she', 'almost', 'lost', 'her', 'mind',
'and', 'now', 'she', 'says', 'she', 'knows',
"you're", 'not', 'the', 'hurting', 'kind',

'she', 'says', 'she', 'loves', 'you',
'and', 'you', 'know', 'that', "can't", 'be', 'bad',
'yes', 'she', 'loves', 'you',
'and', 'you', 'know', 'you', 'should', 'be', 'glad',

'oo', 'she', 'loves', 'you', 'yeah', 'yeah', 'yeah',
'she', 'loves', 'you', 'yeah', 'yeah', 'yeah',
'with', 'a', 'love', 'like', 'that',
'you', 'know', 'you', 'should', 'be', 'glad',

'you', 'know', "it's", 'up', 'to', 'you',
'i', 'think', "it's", 'only', 'fair',
'pride', 'can', 'hurt', 'you', 'too',
'pologize', 'to', 'her',

'Because', 'she', 'loves', 'you',
'and', 'you', 'know', 'that', "can't", 'be', 'bad',
'Yes', 'she', 'loves', 'you',
'and', 'you', 'know', 'you', 'should', 'be', 'glad',

'oo', 'she', 'loves', 'you', 'yeah', 'yeah', 'yeah',
'she', 'loves', 'you', 'yeah', 'yeah', 'yeah',
'with', 'a', 'love', 'like', 'that',
'you', 'know', 'you', 'should', 'be', 'glad',
'with', 'a', 'love', 'like', 'that',
'you', 'know', 'you', 'should', 'be', 'glad',
'with', 'a', 'love', 'like', 'that',
'you', 'know', 'you', 'should', 'be', 'glad',
'yeah', 'yeah', 'yeah',
'yeah', 'yeah', 'yeah', 'yeah'
]

beatles = lyrics_to_frequencies(she_loves_you)
beatles


# In[18]:


def most_common_words(freqs):
    values = freqs.values()
    best = max(freqs.values())
    words = []
    for k in freqs:
        if freqs[k] == best:
            words.append(k)
    return (words, best)

(w, b) = most_common_words(beatles)
w


# In[20]:


def words_often(freqs, minTimes):
    result = []
    done = False
    while not done:
        temp = most_common_words(freqs)
        if temp[1] >= minTimes:
            result.append(temp)
            for w in temp[0]:
                del(freqs[w])  #remove word from dictionary
        else:
            done = True
    return result


# In[21]:


print(words_often(beatles, 5))


# ## Ví dụ - Fibonacci

# In[25]:


def fib_efficient(n, d):
    if n in d:
        return d[n]
    else:
        ans = fib_efficient(n-1, d) + fib_efficient(n-2, d)
        d[n] = ans
        return ans
    
d = {1:1, 2:2}
print(fib_efficient(33, d))


# In[24]:


def fib(x):
    if x == 0 or x == 1:
        return 1
    else:
        return fib(x - 1) + fib(x - 2)
    
print(fib(33))


# ## Biến toàn cục - Global variables

# In[27]:


def fib(n):
    global numFibCalls
    numFibCalls += 1
    if n == 1 or n == 2:
        return n
    else:
        return fib(n-1) + fib(n-2)
    
def fibef(n, d):
    global numFibCalls
    numFibCalls += 1
    if n in d:
        return d[n]
    else:
        ans = fibef(n-1, d) + fibef(n-2, d)
        d[n] = ans
        return ans
    
numFibCalls = 0
fibArg = 34

print(fib(fibArg))
print('function calls', numFibCalls)

numFibCalls = 0

d = {1:1, 2:2}
print(fibef(fibArg, d))
print('function calls', numFibCalls)


# - - -
# [Trước: Tuple và List](http://nbviewer.jupyter.org/github/manleviet/introCSusingPython/blob/master/5%20-%20Tuple%2C%20List.ipynb) | 
# [Mục lục](http://nbviewer.jupyter.org/github/manleviet/introCSusingPython/blob/master/index.ipynb) | 
# [Tiếp: Kiểm thử chương trình](http://nbviewer.jupyter.org/github/manleviet/introCSusingPython/blob/master/7%20-%20Ki%E1%BB%83m%20th%E1%BB%AD%20ch%C6%B0%C6%A1ng%20tr%C3%ACnh.ipynb)