Python - 将字典（将“list”作为值）转换为csv文件

Question

尝试将下面的字典写入具有所需输出的csv文件，如下所述。

dict_data = {"1":["xyz"], 
      "2":["abc","def"], 
      "3":["zzz"] 
      } 

期望的输出：

1,3,2 
xyz,zzz,abc 
     def 

下面代码如预期，因为它使在相同的小区两者“ABC” &“DEF”，如下所示不起作用。

with open('k.csv','wb') as out_file: 
writer = csv.writer(out_file,dialect = 'excel') 
headers = [k for k in dict_data] 
items = [dict_data[k] for k in dict_data] 
writer.writerow(headers) 
writer.writerow(items) 

输出：

1,3,2 
xyz,zzz,abc,def 

Answer 1

下面是完整的解决方案：

import csv 
    import os 

    class CsvfileWriter: 

     ''' 
     Takes dictionary as input and writes items into a CSV file. 

     For ex:- 

     Input dictionary: 

     dict_data = {"1":["xyz"],"2":["abc","def"],"3":["zzz"]} 

     Output: (CSV file) 

     1,3,2 
     xyz,zzz,abc 
     ,,def 

     ''' 

     def __init__(self,dictInput,maxLength=0): 

      ''' 
      Creates a instance with following variables. 
      dictInput & maxLength 

      dictInput -> dictionary having values(list) of same length 

      ex:- 
       dict_data = {"1":["xyz",""],"2":["abc","def"],"3":["zzz",""]} 

      maxLength -> length of the list 

      ''' 
      self.dictInput = dictInput 
      self.maxLength = maxLength 

     @classmethod 
     def list_padding(cls,dictInput): 

      ''' 
      converts input dictionary having list (as values) of varying lenghts into constant length. 
      Also returns class variables dictInput & maxLength 

      Note: 
      dictInput represents the dictionary after padding is applied. 
      maxLength represents the length of the list(values in dictionary) having maximum number of items. 

      Ex:- 

      input dictionary: 

      dict_data = {"1":["xyz"],"2":["abc","def"],"3":["zzz"]} 

      output dictionary: 

      dict_data = {"1":["xyz",""],"2":["abc","def"],"3":["zzz",""]} 


      ''' 
      cls.dictInput = dictInput 
      listValues = dictInput.values() 
      listValues.sort(key = lambda i: len(i)) 
      maxLength = len(listValues[-1]) 

      for i in listValues: 
       while(len(i) < maxLength): 
        i.append('') 

      return cls(dictInput,maxLength) 

     def write_to_csv(self): 

      with open('sample_file.csv','wb') as out_file: 
       writer = csv.writer(out_file,dialect = 'excel') 
       headers = [k for k in self.dictInput] 
       items = [self.dictInput[k] for k in self.dictInput] 
       writer.writerow(headers) 
       c = 0 
       while (c < self.maxLength): 
        writer.writerow([i[c] for i in items]) 
        c += 1 

    dict_data = {"1":["xyz"],"2":["abc","def"],"3":["zzz"]} 

    cf = CsvfileWriter.list_padding(dict_data) 

    cf.write_to_csv() 

Answer 2

下面的作品在Python 2：

import csv 

dict_data = { 
    "1":["xyz"], 
    "2":["abc","def"], 
    "3":["zzz"] 
} 

def transpose(cols): 
    return map(lambda *row: list(row), *cols) 

with open('k.csv','w') as out_file: 
    writer = csv.writer(out_file,dialect = 'excel') 
    headers = dict_data.keys() 
    items = transpose(dict_data.values()) 
    writer.writerow(headers) 
    writer.writerows(items) 

我不能居功transpose函数，我选了你p从here。它将列的列表变成行列表，自动填充None的列太短。幸运的是，csv写入器为None值输出空白，这正是需要的。

（在Python 3，map表现不同（没有填充），所以它需要一些变化。）

编辑：置换transpose功能，无论对于Python 2里的工作和3：

def transpose(cols): 
    def mypop(l): 
     try: 
      return l.pop(0) 
     except IndexError: 
      return '' 
    while any(cols): 
     yield [mypop(l) for l in cols]