python中产生一个矩阵,元素相同且为字符串,另外用 pd.DataFrame构造矩阵
程序是连起来的,为了结果方便观察,我把程序分为几段发
import numpy as np import pandas as pd a=np.full((3, 1), 'no exist') df = pd.DataFrame([['A', 2], ['A', 4], ['B', 6]]) print(a) print(df) #df[1]=df[1].astype(str) df[1]=a#第二列赋值 print(df)
height = 3 width = 5 df_0 = pd.DataFrame(0, index=range(height), columns=range(width)) print(df_0) #df_0[1]=df_0[1].astype(str) df_0[1]=a print(df_0)
b=df_0.at[0,0] print(b) df_0.iloc[2,2] = 1111.67890 print(df_0) df_0= round(df_0,2)#两位小数显示 print(df_0)