如何计算元组列表中的重复项并将其附加为新值答案

【问题标题】：how to count duplicates in a list of tuples and append it as a new value如何计算元组列表中的重复项并将其附加为新值
【发布时间】：2023-01-26 17:43:39
【问题描述】：

output = [('studentA','ISDF'), ('studentB','CSE'),('studentC','BIO'),('studentA','ISDF'), ('studentB','CSE'),('studentC','BIO'),('studentA','ISDF'), ('studentB','CSE'),('studentC','BIO'),('studentA','ISDF'), ('studentB','CSE'),('studentC','BIO'),('studentA','ISDF'), ('studentB','CSE'),('studentC','BIO'),('studentA','ISDF'), ('studentB','CSE'),('studentC','BIO')]

所以上面的列表中总共有 6 组 ('studentA','ISDF'), ('studentB','CSE'),('studentC','BIO')

所以我期待这样的输出~

预期输出 = [('studentA','ISDF',6), ('studentB','CSE',6),('studentC','BIO',6)]

格式应为[('student', 'department', total count)]

【问题讨论】：

标签： python list scripting

【解决方案1】：

你可以使用Counter：

from collections import Counter

output = [('studentA', 'ISDF'), ('studentB', 'CSE'), ('studentC', 'BIO'),
          ('studentA', 'ISDF'), ('studentB', 'CSE'), ('studentC', 'BIO'),
          ('studentA', 'ISDF'), ('studentB', 'CSE'), ('studentC', 'BIO'),
          ('studentA', 'ISDF'), ('studentB', 'CSE'), ('studentC', 'BIO'),
          ('studentA', 'ISDF'), ('studentB', 'CSE'), ('studentC', 'BIO'),
          ('studentA', 'ISDF'), ('studentB', 'CSE'), ('studentC', 'BIO')]

counts = Counter(output)
print(counts)
print([k + (v, ) for k, v in counts.items()])

出去：

Counter({('studentA', 'ISDF'): 6, ('studentB', 'CSE'): 6, ('studentC', 'BIO'): 6})
[('studentA', 'ISDF', 6), ('studentB', 'CSE', 6), ('studentC', 'BIO', 6)]

【讨论】：

【解决方案2】：

使用集合中的 Counter() 和列表理解

from collections import Counter

count = Counter(output)
exp_output = [(key[0], key[1], value) for key, value in count.items()]
print(exp_output)

[('studentA', 'ISDF', 6), ('studentB', 'CSE', 6), ('studentC', 'BIO', 6)]

【讨论】：

【解决方案3】：

尝试这个：

sorted([tuple(list(item)+[output.count(item)]) for item in set(output)])

【讨论】：