Question

我有以下数据框

   Q  A
A  a  h  
A  b  i
A  c  j
B  d  k
B  a  l 
B  b  m
C  c  n

我想得到假和groupby

    a   b   c   d    e   f   g
A   h   i   j  nan  nan nan nan
B   l  nan nan nan  k   nan nan      
C  nan nan  n  nan  nan nan nan

col=df.Q

我必须申请get_dummies和groupby。但我无法理解。

我怎样才能得到这个结果？

Answer 1

您似乎需要reset_index与pivot：

df = df.reset_index().pivot(index='index', columns='Q', values='A')
print (df)
Q         a     b     c     d
index                        
A         h     i     j  None
B         l     m  None     k
C      None  None     n  None

然后，如果有必要reindex_axis和replace：

cols = list('abcdefg')
print (df.reindex_axis(cols, axis=1).replace({None:np.nan}))
Q        a    b    c    d   e   f   g
index                                
A        h    i    j  NaN NaN NaN NaN
B        l    m  NaN    k NaN NaN NaN
C      NaN  NaN    n  NaN NaN NaN NaN

编辑：

如果groupby join print (df) Q A A a h A b i A c j B d k B a l B b m <-duplicates B b B b t <-duplicates B b C c n df = df.reset_index().groupby(['index','Q'])['A'].apply(','.join).unstack() print (df) Q a b c d index A h i j None B l m,t None k C None None n None与#aggfunc='first' - get only first value, another values are lost df1 = df.reset_index().pivot_table(index='index', columns='Q', values='A', aggfunc='first') print (df1) Q a b c d index A h i j None B l m None k C None None n None Q a b c d #aggfunc='sum' - summed data, no separator df2 = df.reset_index().pivot_table(index='index', columns='Q', values='A', aggfunc='sum') print (df2) index A h i j None B l mt None k C None None n None Q a b c d #aggfunc=','.join - summed data with separator df3 = df.reset_index().pivot_table(index='index', columns='Q', values='A', aggfunc=','.join) print (df3) index A h i j None B l m,t None k C None None n None的重复数据更好：

@OneToMany(mappedBy="cliente")

pivot_table的另一种可能解决方案：

class MyClass : ... {
  QGraphicsScene m_scene;
  QGraphicsPixmapItem m_pixmapItem; // must be after m_scene: in C++ this order matters!
  ...
}

MyClass::MyClass() {
  ...
  m_scene->addItem(&m_pixmapItem);
}

void MyClass::myMethod() {
  m_pixmapItem.setPixmap(QPixmap::fromImage(LifeGrid));
}

如何获得假人和群体

1 个答案: