week1 -learn python 5 字典功能

以下代码中运用了字典功能，用于计算文本中字符串出现的频率；其中{}代表创建一个可填入的dictionary，类似于array

# Insert your completed FrequencyMap() function here.

def FrequencyMap(Text, k):

    # your code here

    freq = {}#代表字典

    n = len(Text)

    for i in range(n-k+1):

        Pattern = Text[i:i+k]

        if Pattern in freq:

            freq[Pattern]+=1

        else:

            freq[Pattern]=1

# hint: your code goes here!

    return freq

values（）内置函数，用于返回dictionary 中含有的值

m=max(freq.values())#返回频率最大的值

def FrequentWords(Text, k):

    words = []#代表列表

    freq = FrequencyMap(Text, k)

    m = max(freq.values())

    for key in freq:

        # add each key to words whose corresponding frequency value is equal to m

        if freq[key]==m:

            pattern=key

            words.append(pattern)# 如需将项目添加到列表的末尾，请使用 append() 方法

    return words

    # your code here

    for key in freq:

        # add each key to words whose corresponding frequency value is equal to m    return words