[英]Convert list of dicts to CSV
我正在尝试将此字典列表转换为csv,首先我的数据包含在Counter
字典中,但是由于它像字典,因此我认为使用它与字典是一样的。 所以这就是我要做的:
我的反对意见是这样的:
counterdict = {1:Counter({u'a':1, u'b':1, u'c':3}),2:Counter({u'd':1, u'f':4, u'e':2})...}
我将其转换为像这样的字典列表:
new_dict = [dict(d,Month=k) for k, d in counterdict.iteritems()]
要得到 :
new_dict = [{Month :1, u'a':1, u'b':1, u'c':3}, {Month : 2,u'd':1, u'f':4, u'e':2}...]
然后我想将new_dict数据转换为csv:
out_path= "outfile.csv"
out_file = open(out_path, 'wb')
new_dict = [dict(d,Month=k) for k, d in counterdict.iteritems()]
writer = DictWriter(out_file, fieldnames=allFields, dialect='excel')
for row in new_dict:
writer.writerow(row)
out_file.close()
但是我得到了错误:
Traceback (most recent call last):
File "C:/wamp/www/metrics1/script/cgi/translate_parameters.py", line 333, in <module>
writer.writerow(row)
File "C:\Python27\lib\csv.py", line 148, in writerow
return self.writer.writerow(self._dict_to_list(rowdict))
File "C:\Python27\lib\csv.py", line 141, in _dict_to_list
wrong_fields = [k for k in rowdict if k not in self.fieldnames]
TypeError: argument of type 'NoneType' is not iterable
请帮助!!
编辑:
allFields
来自counterdict
这样的价值观:
allFields = list(set().union(*counterdict.values()))
因此,这给了我所有反驳领域的清单。
您将fieldnames
参数设置为None
; 您需要确保allFields
是字符串的有序序列。
演示问题的演示:
>>> from cStringIO import StringIO
>>> import csv
>>> w = csv.DictWriter(StringIO(), fieldnames=None)
>>> w.writerow({'foo':'bar'})
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/opt/lib/python2.7/csv.py", line 148, in writerow
return self.writer.writerow(self._dict_to_list(rowdict))
File "/opt/lib/python2.7/csv.py", line 141, in _dict_to_list
wrong_fields = [k for k in rowdict if k not in self.fieldnames]
TypeError: argument of type 'NoneType' is not iterable
>>> w = csv.DictWriter(StringIO(), fieldnames=['foo'])
>>> w.writerow({'foo':'bar'})
这个任务是使用诸如pandas之类的库的绝好机会,该库可自动处理字典列表。 做:
import pandas as pd
df = pd.DataFrame(list_of_dicts)
df = df.set_index("first_column")
df.to_csv("filename")
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