统计文件中每个字母的个数

缺乏、安全感 2022-06-12 14:20 286阅读 0赞

关键点： 编写一个程序，提示用户输入一个文件名称，然后统计在不计大小写的情况下每个字符的出现次数。

解决思路：  
1.将文件中的每一行作为字符串读取。  
2.使用字符串的lower()函数将大写字符转换成小写。  
3.创建含有26个整型值得名为counts 的列表，每个值是对每个字母出现次数的统计，比如 counts\[1\]统计的是‘b’出现的次数。  
4.对于每个字符，判断其是否为小写字母（使用 isalpha()函数）。如果是，则将列表中的相应计数器加1.  
5.最后，显示统计结果。  
代码如下：

def main():
        filename = input("Enter a filename:").strip()
        infile = open(filename,"r")  #open the file
    
        counts = 26*[0]
        for line in infile:
            #Invoke the CountLetters function to count each letter
            countLetters(line.lower(),counts)
    
        for i in range(len(counts)):
            if counts[i] != 0:
                print(chr(ord('a')+ i) + " appears " + str(counts[i]) + (" time" if counts[i]==1 else " times"))
        infile.close()
    
    #Count each letter in the string
    def countLetters(line,counts):
        for ch in line:
            if ch.isalpha():
                counts[ord(ch) - ord('a')] += 1
    
    main()

Enter a filename:input.txt
    a appears 2 times
    b appears 1 time
    c appears 1 time
    d appears 5 times
    e appears 6 times
    f appears 7 times
    h appears 1 time
    i appears 3 times
    j appears 13 times
    k appears 1 time
    l appears 1 time
    m appears 1 time
    n appears 3 times
    o appears 3 times
    p appears 5 times
    q appears 1 time
    s appears 7 times
    v appears 1 time
    w appears 2 times
    x appears 2 times