Mastering pandas - Second Edition

Pivots and reshaping data

This section deals with how you can reshape data. Sometimes, data is stored in what is known as a stacked format. Here is an example of stacked data using the PlantGrowth dataset:

    In [344]: plantGrowthRawDF=pd.read_csv('./PlantGrowth.csv')
           plantGrowthRawDF
    Out[344]:   observation   weight  group
            0   1      4.17  ctrl
            1   2      5.58  ctrl
            2   3      5.18  ctrl
            ...
            10       1        4.81    trt1
            11       2        4.17    trt1
            12       3        4.41    trt1
           ... 
            20       1        6.31    trt2
            21       2        5.12    trt2
            22       3        5.54    trt2
  

This data consists of results from an experiment that compared the dried weight yields of plants that were obtained under a control (ctrl) and two different treatment conditions (trt1 and trt2). Suppose we wanted to do some analysis on this data by group value. One way to ...