Pandas's apply and map, Applymap

Apply
Apply to perform a whole operation on a column

In [116]: frame = Dataframe (Np.random.randn (4, 3), columns=list (' BDE '), index=[' Utah ', ' Ohio ', ' Texas ', ' Oregon '])

In [117]: Frame
out[117]: 
               b         d         e
Utah   -0.029638  1.081563  1.280300
Ohio    0.647747  0.831136-1.549481
Texas   0.513416-0.884417  0.195343
oregon-0.485454-0.477388- 0.309548 in

[118]: F = lambda X:x.max ()-x.min () in

[119]: Frame.apply (f)
out[119]: 
b    1.133201
d    1.965980
e    2.829781
Dtype:float64

Applymap
Applymap the conversion of each element in a Dataframe

In [click]: Format = lambda x: '%.2f '% x in

[121]: Frame.applymap (format)
out[121]: 
            b      d      e
Utah    -0.03   1.08   1.28
Ohio     0.65   0.83  -1.55
Texas    0.51  -0.88   0.20
Oregon  -0.49  -0.48  -0.31

Map
Applymap the conversion of each element in a series

in [122]: frame[' e '].map (format) out[122]: Utah 1.28 Ohio-1.55 Texas 0.20-Orego n-0.31 Name:e, Dtype:object