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我有一个数据框 df
,它有 'TPrice','THigh','TLow','TOpen','TClose','TPCLOSE'
列,和现在我想将 'TPrice','THigh','TLow','TOpen','TClose'
列值设置为与 'TPCLOSE'
列相同TPrice
列值为零的行。
显示一些 TPrice 为 0 的行:
>>> df[df['TPrice']==0][['TPrice','THigh','TLow','TOpen','TClose','TPCLOSE']][0:5]
TPrice THigh TLow TOpen TClose TPCLOSE
13 0 0 0 0 0 4.19
19 0 0 0 0 0 7.74
32 0 0 0 0 0 3.27
43 0 0 0 0 0 12.98
60 0 0 0 0 0 7.48
然后赋值:
>>> df[df['TPrice']==0][['TPrice','THigh','TLow','TOpen','TClose']] = df['TPCLOSE']
但 Pandas 并没有真正改变 df ,因为下面的代码仍然可以找到一些行:
>>> df[df['TPrice']==0][['TPrice','THigh','TLow','TOpen','TClose','TPCLOSE']][0:5]
TPrice THigh TLow TOpen TClose TPCLOSE
13 0 0 0 0 0 4.19
19 0 0 0 0 0 7.74
32 0 0 0 0 0 3.27
43 0 0 0 0 0 12.98
60 0 0 0 0 0 7.48
那怎么办呢?
Jeff 解决方案更新:
>>> quote_df = get_quote()
>>> quote_df[quote_df['TPrice']==0][['TPrice','THigh','TLow','TOpen','TClose','TPCLOSE','RT','TVol']][0:5]
TPrice THigh TLow TOpen TClose TPCLOSE RT TVol
13 0 0 0 0 0 4.19 -100 0
32 0 0 0 0 0 3.27 -100 0
43 0 0 0 0 0 12.98 -100 0
45 0 0 0 0 0 26.74 -100 0
60 0 0 0 0 0 7.48 -100 0
>>> row_selection = quote_df['TPrice']==0
>>> col_selection = ['THigh','TLow','TOpen','TClose']
>>> for col in col_selection:
... quote_df.loc[row_selection, col] = quote_df['TPCLOSE']
...
>>> quote_df[quote_df['TPrice']==0][['TPrice','THigh','TLow','TOpen','TClose','TPCLOSE','RT','TVol']][0:5]
TPrice THigh TLow TOpen TClose TPCLOSE RT TVol
13 0 4.19 4.19 4.19 4.19 4.19 -100 0
32 0 4.19 4.19 4.19 4.19 3.27 -100 0
43 0 4.19 4.19 4.19 4.19 12.98 -100 0
45 0 4.19 4.19 4.19 4.19 26.74 -100 0
60 0 4.19 4.19 4.19 4.19 7.48 -100 0
>>>