Python系列在数据框错误

时间：2018-01-17 13:52:52

标签： python pandas dataframe

这是数据帧并使用它我正在进行逻辑操作，抛出错误如下。我怎样才能克服这个问题？

Traceback (most recent call last):
    in <module>
    if( eoddf['High'][Open] > linebreakvalue):
  File "", line , in __nonzero__
    .format(self.__class__.__name__))
ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().

逻辑低于表格：

eoddf :(数据帧）

           Symbol Series  Prev Close    Open    High     Low    Last   Close  \
Date                                                                           
2015-01-01   SBIN     EQ      311.85  312.45  315.00  310.70  314.00  314.00   
2015-01-02   SBIN     EQ      314.00  314.35  318.30  314.35  315.60  315.25   
2015-01-05   SBIN     EQ      315.25  316.25  316.80  312.10  312.80  312.75   
2015-01-06   SBIN     EQ      312.75  310.00  311.10  298.70  299.90  299.90   
2015-01-07   SBIN     EQ      299.90  300.00  302.55  295.15  301.40  300.15   
2015-01-08   SBIN     EQ      300.15  305.00  306.50  302.35  305.25  304.85   
2015-01-09   SBIN     EQ      304.85  306.70  307.85  302.00  303.00  303.20   
2015-01-12   SBIN     EQ      303.20  304.15  307.80  301.10  306.90  307.10   
2015-01-13   SBIN     EQ      307.10  308.15  310.75  304.15  305.25  305.10   
2015-01-14   SBIN     EQ      305.10  304.00  307.00  302.25  305.00  304.70   
2015-01-15   SBIN     EQ      304.70  319.90  323.70  314.00  318.40  320.30   
2015-01-16   SBIN     EQ      320.30  320.00  320.30  313.10  315.25  315.45   
2015-01-19   SBIN     EQ      315.45  316.55  317.95  312.50  313.20  313.15   
2015-01-20   SBIN     EQ      313.15  314.00  319.80  314.00  318.00  318.15   
2015-01-21   SBIN     EQ      318.15  319.90  327.60  319.00  326.00  326.20   
2015-01-22   SBIN     EQ      326.20  326.90  327.60  321.80  325.20  324.65   
2015-01-23   SBIN     EQ      324.65  328.25  332.55  324.65  327.05  327.45   
2015-01-27   SBIN     EQ      327.45  329.40  332.15  322.60  331.45  330.05   
2015-01-28   SBIN     EQ      330.05  330.40  336.00  328.20  333.40  334.60

代码：

 for Open in range(1, len(eoddf)):
     if( eoddf['High'][Open] > linebreakvalue):
        eoddf['LBHigh']{Open]=eoddf['High'][Open]
        eoddf['LBLow'][Open] =eoddf['Low'][Open]
        linebreakvalue = eoddf['LBHigh'][Open]
     if( eoddf['Low'][Open] < linebreakvalue):
        eoddf['LBHigh'][Open]=eoddf['Low'][Open]
        eoddf['LBLow'][Open] =eoddf['High'][Open]
        linebreakvalue = eoddf['LBLow'][Open]

我正在尝试将此MQ4代码写入Python以满足我的需要。代码参考位于：http://www.35pip.com/metatrader-indicators/indicators/3LineBreak.mq4

我还想运行这个循环，直到Open列的最后一个条目为止，或者在这里可以使用其他方法吗？

基本上我正在尝试将这段代码转换为Python 

OLDSwing=Swing;
VALUE1=High[Highest(NULL,0,MODE_HIGH,Lines_Break,shift+1)];
VALUE2= Low[Lowest(NULL,0,MODE_LOW,Lines_Break,shift+1)];
if (OLDSwing==1 &&  Low[shift]<VALUE2) Swing=-1;
if (OLDSwing==-1 && High[shift]>VALUE1 ) Swing=1;
if (Swing==1) 
   { HighBuffer[shift]=High[shift]; LowBuffer[shift]=Low[shift]; }
if (Swing==-1)
{ LowBuffer[shift]=High[shift]; HighBuffer[shift]=Low[shift]; }

这个规则是：

  • 如果价格超过上一行的高价，则会绘制一条新的绿线
  • 如果价格低于前一行的低价，则会绘制一条新的红线
  • 如果价格没有高于或低于前一行，则不会产生任何结果
  • 如果反弹足够强大以形成三条连续的绿线，那么只有当价格低于最后三条绿线的最低点时才会绘制新的红线
  • 如果抛售足够强大以形成三条连续的红线，那么只有当价格上涨超过最后三条红线的最高点时才会绘制新的绿线。

这样做的最佳方式是什么？

2 个答案:

答案 0 :(得分：3)

这就是你所寻求的：

eoddf['LBHigh'] = df.apply(lambda x: x['High'] if x['High'] > linebreakvalue else x['Low'], axis=1)
eoddf['LBLow'] = df.apply(lambda x: x['Low'] if x['Low'] < linebreakvalue else x['High'], axis=1)

答案 1 :(得分：2)

我相信你需要加倍numpy.where，但如果相等则条件返回第二个值：

linebreakvalue = 320
m1 = eoddf['High'] > linebreakvalue
m2 = eoddf['Low'] > linebreakvalue

eoddf['LBHigh']= np.where(m1, eoddf['High'], eoddf['Low'])
eoddf['LBLow'] = np.where(m2, eoddf['Low'], eoddf['High'])

print (eoddf)

           Symbol Series  Prev Close    Open    High     Low    Last   Close  \
2015-01-01   SBIN     EQ      311.85  312.45  315.00  310.70  314.00  314.00   
2015-01-02   SBIN     EQ      314.00  314.35  318.30  314.35  315.60  315.25   
2015-01-05   SBIN     EQ      315.25  316.25  316.80  312.10  312.80  312.75   
2015-01-06   SBIN     EQ      312.75  310.00  311.10  298.70  299.90  299.90   
2015-01-07   SBIN     EQ      299.90  300.00  302.55  295.15  301.40  300.15   
2015-01-08   SBIN     EQ      300.15  305.00  306.50  302.35  305.25  304.85   
2015-01-09   SBIN     EQ      304.85  306.70  307.85  302.00  303.00  303.20   
2015-01-12   SBIN     EQ      303.20  304.15  307.80  301.10  306.90  307.10   
2015-01-13   SBIN     EQ      307.10  308.15  310.75  304.15  305.25  305.10   
2015-01-14   SBIN     EQ      305.10  304.00  307.00  302.25  305.00  304.70   
2015-01-15   SBIN     EQ      304.70  319.90  323.70  314.00  318.40  320.30   
2015-01-16   SBIN     EQ      320.30  320.00  320.30  313.10  315.25  315.45   
2015-01-19   SBIN     EQ      315.45  316.55  317.95  312.50  313.20  313.15   
2015-01-20   SBIN     EQ      313.15  314.00  319.80  314.00  318.00  318.15   
2015-01-21   SBIN     EQ      318.15  319.90  327.60  319.00  326.00  326.20   
2015-01-22   SBIN     EQ      326.20  326.90  327.60  321.80  325.20  324.65   
2015-01-23   SBIN     EQ      324.65  328.25  332.55  324.65  327.05  327.45   
2015-01-27   SBIN     EQ      327.45  329.40  332.15  322.60  331.45  330.05   
2015-01-28   SBIN     EQ      330.05  330.40  336.00  328.20  333.40  334.60   

            LBHigh   LBLow  
2015-01-01  310.70  315.00  
2015-01-02  314.35  318.30  
2015-01-05  312.10  316.80  
2015-01-06  298.70  311.10  
2015-01-07  295.15  302.55  
2015-01-08  302.35  306.50  
2015-01-09  302.00  307.85  
2015-01-12  301.10  307.80  
2015-01-13  304.15  310.75  
2015-01-14  302.25  307.00  
2015-01-15  323.70  323.70  
2015-01-16  320.30  320.30  
2015-01-19  312.50  317.95  
2015-01-20  314.00  319.80  
2015-01-21  327.60  327.60  
2015-01-22  327.60  321.80  
2015-01-23  332.55  324.65  
2015-01-27  332.15  322.60  
2015-01-28  336.00  328.20

但如果确实需要循环：

for i, x in eoddf.iterrows():
    if(eoddf.loc[i, 'High'] > linebreakvalue):
       eoddf.loc[i, 'LBHigh']=eoddf.loc[i,'High']
       eoddf.loc[i,'LBLow'] =eoddf.loc[i,'Low']
    if(eoddf.loc[i,'Low'] < linebreakvalue):
       eoddf.loc[i,'LBHigh']=eoddf.loc[i,'Low']
       eoddf.loc[i,'LBLow'] =eoddf.loc[i,'High']
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