將列表轉換爲行

Question

在Python中將列表轉換爲單獨元素的有效方法是什麼？

我有一個看起來像這樣的數據集;

['StudentA','80','94','93'] 
['StudentB','93','94'] 

我想重新塑造數據，以便每個學生/分數都有自己的行;

['StudentA','80'] 
['StudentA','94'] 
etc... 

Answer 1

你可以使用一個列表的理解，這樣的：

data = ['StudentA','80','94','93'] 
res = [[data[0], x] for x in data[1:]] 

這臺res到[['StudentA', '80'], ['StudentA', '94'], ['StudentA', '93']]。

Answer 2

c=['StudentA','80','94','93'] 

    d=[[c[0], p] for p in c[1:]] 

Answer 3

如果它包含這些行的列表（all_students），你可以做你想做的，做：

result = [] 
for student in all_students: 
    student_name = student[0] 
    result.extend([[student_name, value] for value in student[1:]] 
print(result) 

Answer 4

夫婦學生使用dictionary其各自的數據用。

def to_dict(l): 
    d = {} 
    for i in l: 
     key = i[0] 
     value = i[1:] 
     d[key] = value 
    return d  

輸出示例：

l = [['studentA', 90, 90],['studentB', 78, 40]] 
print to_dict(l) 
>>> {'studentB': [78, 40], 'studentA': [90, 90]} 
for key, value in d.iteritems(): 
    for i in value: 
     print key, i 
>>> studentB 78 
>>> studentB 40 
>>> studentA 90 
>>> studentA 90 

Answer 5

這個字典解析會組你的數據由學生姓名：

d = {x[0]: x[1:] for x in dataset} 

即：

>>> d 
{'StudentA': ['80', '94', '93'], 'StudentB': ['93', '94']} 

從您可以使用嵌套循環或列表理解提取單個對：

>>> [(k, w) for k, v in d.items() for w in v] 
[('StudentA', '80'), ('StudentA', '94'), ('StudentA', '93'), ('StudentB', '93'), ('StudentB', '94')]