>>> s='alex egon alex yuyang yuyang yuyang' >>> s_ls = s.split() >>> s_ls ['alex', 'egon', 'alex', 'yuyang', 'yuyang', 'yuyang'] >>> dic = {} >>> for i in s_ls: if i not in dic: dic[i]=1 else: dic[i]+=1 >>> dic {'alex': 2, 'egon': 1, 'yuyang': 3} >>> for i in dic.items(): print(i) ('alex', 2) ('egon', 1) ('yuyang', 3) >>> ls = [] >>> for i in dic.items(): ls.append(i) >>> ls [('alex', 2), ('egon', 1), ('yuyang', 3)] >>> ls.sort(key=lambda x:x[1]) >>> ls [('egon', 1), ('alex', 2), ('yuyang', 3)] >>>