python统计字符串中字母出现的频次，以字典形式呈现。

统计字符串中字母出现的频次，以字典形式呈现。
参考下面的例子，把空白处补充完整。

_______ ______   #导入re库函数

str1='''When I wrote the following pages, or rather the bulk of them, I lived alone, in the woods, a mile from any neighbor,  

in a house which I had built myself, on the shore of Walden Pond, in Concord, Massachusetts,  

and earned my living by the labor of my hands only.  

I lived there two years and two months. At preset I am a sojourner in civilized life again.'''

 

text=re.____(_____,_____,______)  #删除str1中的标点符号

dict1=_______    #定义一个空字典

for each in ______ :   #轮询text中的每个字符

   if each==' ' or each =='\n':   #如果是空格或者换行符，则忽略。

       continue

   elif each not in dict1.keys():

       ___________    

   else:

       ___________

print(dict1)



import re
str1='''When I wrote the following pages, or rather the bulk of them, I lived alone, in the woods, a mile from any neighbor,  
in a house which I had built myself, on the shore of Walden Pond, in Concord, Massachusetts,  
and earned my living by the labor of my hands only.  
I lived there two years and two months. At preset I am a sojourner in civilized life again.'''
text=re.sub('[.,]' ,' ',str1)  #删除str1中的标点符号
# print(text)
dict1= {}    #定义一个空字典
for each in text :   #轮询text中的每个字符
   if each==' ' or each =='\n':   #如果是空格或者换行符，则忽略。
       continue
   elif each not in dict1.keys():
       dict1[each] = 1
   else:
       dict1[each] += 1
print(dict1)

import re

str1='''When I wrote the following pages, or rather the bulk of them, I lived alone, in the woods, a mile from any neighbor,  
in a house which I had built myself, on the shore of Walden Pond, in Concord, Massachusetts,  
and earned my living by the labor of my hands only.  
I lived there two years and two months. At preset I am a sojourner in civilized life again.'''
text=re.sub(r'[,\.]', '',str1, re.DOTALL)  #删除str1中的标点符号
dict1= {}    #定义一个空字典
for each in text:   #轮询text中的每个字符
   if each==' ' or each =='\n':   #如果是空格或者换行符，则忽略。
      continue
   elif each not in dict1.keys():
      dict1[each] = 1    
   else:
      dict1[each] += 1    
print(dict1)



import re   #导入re库函数
str1='''When I wrote the following pages, or rather the bulk of them, I lived alone, in the woods, a mile from any neighbor,  
in a house which I had built myself, on the shore of Walden Pond, in Concord, Massachusetts,  
and earned my living by the labor of my hands only.  
I lived there two years and two months. At preset I am a sojourner in civilized life again.'''
 
text=re.sub(r'[,.]',"",str1)  #删除str1中的标点符号
dict1=dict()    #定义一个空字典
for each in text :   #轮询text中的每个字符
   if each==' ' or each =='\n':   #如果是空格或者换行符，则忽略。
       continue
   elif each not in dict1.keys():
       dict1[each]=1
   else:
       dict1[each]+=1
print(dict1)

换种算法可能更好。
1、轮询字符串中非字母字符列表(标点回车和空格)',.: \n' ，用str.replace(char, '')方法去除。
2、利用set()特性获取组成字符串的字母列表。
3、轮询字符串组成字母列表，用str.count(char)方法统计字母出现频次并写入统计频次字典。

代码(不可以用在IDE中调试好的代码，只好用截图了）

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输出

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