写入cvs失败
我使用以下代码将数据保存到cvs文件中：
filename='shareListing.csv'
allshares=pd.read_csv(filename)
i=0
for item in allshares['Code']:
try:
print item
ebitdata=fdata(item)
allshares.loc[:,('endDate')][i]=ebitdata[0]
allshares.loc[:,('EBIT')][i] = ebitdata[1]
print ebitdata[1]
except Exception, e:
allshares.loc[:,('EBIT')][i] = ['NA']
allshares.to_csv('results.csv')shareListing.csv看起来如下(endDate和EBIT列为空)：
代码shortName endDate
000001.XSHE平安银行
000002.XSHE万科A
000003.XSHE金田A
000004.XSHE国农科技
000005.XSHE世纪星源
000006.XSHE深振业A
还有一个名为fdata的函数，它为每个特定项返回"endDate“和"EBIT”。
在执行时，我得到了以下信息：
000001.XSHE
E:/Python/py27/DataYes/Prices.py:91: SettingWithCopyWarning:
A value is trying to be set on a copy of a slice from a DataFrame请参阅文档中的注意事项：http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy
allshares.loc[:,('EBIT')][i] = ['NA']
000002.XSHE
C:\Users\ly\python27\lib\site-packages\pandas\core\indexing.py:179: SettingWithCopyWarning:
A value is trying to be set on a copy of a slice from a DataFrame请参阅文档中的注意事项：http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy
self._setitem_with_indexer(indexer, value)
E:/Python/py27/DataYes/Prices.py:85: SettingWithCopyWarning:
A value is trying to be set on a copy of a slice from a DataFrame请参阅文档中的注意事项：http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy
allshares.loc[:,('endDate')][i]=ebitdata[0]
20901592186.7
000003.XSHE我遵循文档并使用.loc更改了索引函数，但是仍然是相同的消息，而results.csv文件只在endDate和EBIT列中填充了第一个条目，其余的都是空的。
请帮帮忙。
回答 1
Stack Overflow用户
发布于 2017-11-20 07:55:21
我认为你需要改变：
allshares.loc[:,('endDate')][i]=ebitdata[0]
allshares.loc[:,('EBIT')][i] = ebitdata[1]
allshares.loc[:,('EBIT')][i] = ['NA']至：
allshares.loc[i,'endDate'] = ebitdata[0]
allshares.loc[i,'EBIT'] = ebitdata[1]
allshares.loc[i,'EBIT'] = 'NA' 或者如果需要丢失值NaN
allshares.loc[i,'EBIT'] = np.nan更好的解决方案是在函数中捕获Exception并返回Series，然后使用apply for循环：
allshares = pd.DataFrame({'Code':list('abcdef'),
'B':[4,5,4,5,5,4]})
def fdata(x):
try:
#rewrite to your code
if x != 'e':
#return Series instead tuple
return pd.Series([x * 2, x * 3])
else:
#some sample exception for e value
allshares['not exist']
except Exception as e:
#return Series instead tuple
return pd.Series(['NA', 'NA'])
#for NaNs
#return pd.Series([np.nan, np.nan])
allshares[['endDate','EBIT']] = allshares['Code'].apply(fdata)
print (allshares)
B Code endDate EBIT
0 4 a aa aaa
1 5 b bb bbb
2 4 c cc ccc
3 5 d dd ddd
4 5 e NA NA
5 4 f ff fff但是，如果change函数fdata为阴极异常和返回序列创建了另一个函数：
def fdata(x):
if x != 'e':
return (x * 2, x * 3)
else:
return allshares['not exist']
def func(x):
try:
return pd.Series(fdata(x))
except Exception as e:
return pd.Series(['NA', 'NA'])
#return pd.Series([np.nan, np.nan])
allshares[['endDate','EBIT']] = allshares['Code'].apply(func)
print (allshares)
B Code endDate EBIT
0 4 a aa aaa
1 5 b bb bbb
2 4 c cc ccc
3 5 d dd ddd
4 5 e NA NA
5 4 f ff fffhttps://stackoverflow.com/questions/47387303
复制相似问题
腾讯云开发者
