python - 返回列中选择值的百分比计数

Question

我有当前的代码，然后是一个如下系列的打印输出

shapes = ['triangle','circle','square']
max_shape = None
max_percent = None
for shape in shapes:
    df_overall = df[(df['Shape']== shape)]
    num_overall = df_overall.shape[0]
    shape_df = df
    num_total = shape_df.shape[0]
    percentage_overall = num_overall / num_total


    if max_shape is None: 



        print(shape, percentage_overall)

它给了我形状列中每个值的百分比作为一个系列，

triangle 0.672
circle 0.16
square 0.168

我可以代替打印到系列，而是将输出检索为数据帧吗？

Answer 1

放弃循环，您可以通过 value_counts 将其矢量化:

df = pd.DataFrame({'Shape': ['triangle'] * 3 + ['square'] * 2 + ['trapezoid'] * 5})
shapes = ['triangle', 'square']

df.loc[df['Shape'].isin(shapes), 'Shape'].value_counts().div(len(df)).to_frame() 

          Shape
triangle    0.3
square      0.2

“我可以将其输出为帧而不是系列吗”是通过调用 to_frame() 解决的一个微不足道的问题。结果上。