记录python2（二）

统计文本中每个字符出现的次数，打印前三

初级版：（if-else + 冒泡排序）

res = {}with open('demo.txt') as f:    for char in f.read().replace(' ',''):        if char in res:            res[char] = res[char] + 1        else:            res[char] = 1res_list = res.items()length = len(res_list)for i in range(length - 1):    for j in range(length - 1):        if res_list[j][1] < res_list[j+1][1]:            res_list[j], res_list[j+1] = res_list[j+1], res_list[j]for i in range(3):    print '%s count is %d' % (res_list[i][0],res_list[i][1])

进阶版：

res = {}with open('SSHClient.py') as f:    for char in f.read().replace(' ',''):        res[char] = res.get(char,0) + 1for c,num in sorted(res.items(),key=lambda x:x[1],reverse=True)[:3]:    print '%s count is %d' % (c,num)