python 文件读取运用问题

Question

“”“
这是一段读取文件，统计文件中相同字母出现的频率的代码，然后在屏幕输出，虽然能统计相同字符的出现频率，但大写和小写系统
还是认为是2个字母，谁能指点一下，还有最好用lambda函数来表达同一个字符出现的频率
”“”
from os import strerror
counters = {chr(ch): 0 for ch in range(ord('a'), ord('z') + 1)}
print(counters)
file_name = input("Enter the name of the file to analyze: ")
try:
    f = open("textfile.txt", "rt")
    for line in f:
        for char in line:
            if char.isalpha():
                char.lower()
                x=set(line)
    f.close()
    for item in x:
        counters[item]=line.count(item.lower())
        cnt=counters[item]
        if cnt > 0:
            print(item, '->',cnt)
except IOError as e:
    print("I/O error occurred: ", strerror(e.errno))
"""
output:
输入cbaBaa
输出
a -> 3
c -> 1
b -> 2

Answer 1

将字符全部转换为大写或者小写

“”“
这是一段读取文件，统计文件中相同字母出现的频率的代码，然后在屏幕输出，虽然能统计相同字符的出现频率，但大写和小写系统
还是认为是2个字母，谁能指点一下，还有最好用lambda函数来表达同一个字符出现的频率
”“”
from os import strerror
counters = {chr(ch): 0 for ch in range(ord('a'), ord('z') + 1)}
print(counters)
file_name = input("Enter the name of the file to analyze: ")
try:
    f = open("textfile.txt", "rt")
    for line in f:
      for char in line:
            if char.isalpha():
                char.lower()
                x=set(line)

                
     
    f.close()
    for item in x:
        str=item.lower()
        counters[str]=line.count(str)
        cnt=counters[str]
        if cnt > 0:
            print(str, '->',cnt)
except IOError as e:
   pass