我想将所有SkinThickness
的零值分配给每个患者的平均值
处于Age
的特定范围内。
因此,我将数据帧按Age
分组,以获取每个年龄段的SkinThickness
的平均值。
为了将SkinThickness
列中的每个零值分配给根据年龄分组计算出的相应平均值。
ageSkinMean = df_clean.groupby("Age_Class")["SkinThickness"].mean()
>>> ageSkinMean
Age_Class
21-22 years 82.163399
23-25 years 103.171429
26-30 years 91.170254
31-38 years 80.133028
39-47 years 73.685851
48-58 years 89.130233
60+ years 40.899160
Name: Insulin, dtype: float64
目前,我正在运行的代码太少了……使用iterrows()
start = time.time()
for i, val in df_clean[df_clean.SkinThickness == 0].iterrows():
if val[7] < 22:
df_clean.loc[i, "SkinThickness"] = ageSkinMean[0]
elif val[7] < 25:
df_clean.loc[i, "SkinThickness"] = ageSkinMean[1]
elif val[7] < 30:
df_clean.loc[i, "SkinThickness"] = ageSkinMean[2]
elif val[7] < 38:
df_clean.loc[i, "SkinThickness"] = ageSkinMean[3]
elif val[7] < 47:
df_clean.loc[i, "SkinThickness"] = ageSkinMean[4]
elif val[7] < 58:
df_clean.loc[i, "SkinThickness"] = ageSkinMean[5]
else:
df_clean.loc[i, "SkinThickness"] = ageSkinMean[6]
print(time.time() - start)
我想知道是否有任何 pandas 优化以使这样的代码块运行更快
答案 0 :(得分:1)
您可以使用pandas转换功能将SkinThickness 0值替换为平均值
age_skin_thickness_mean = df_clean.groupby('Age_Class')['SkinThickness'].mean()
def replace_with_mean_thickness(row):
row['SkinThickness'] = age_skin_thickness_mean[row['Age_Class']]
return row
df_clean.loc[df_clean['SkinThickness'] == 0] = df_clean.loc[df_clean['SkinThickness'] == 0].transform(replace_with_mean_thickness, axis=1)
df_clean中所有SkinThickness == 0的行现在将具有等于其年龄组平均值的SkinThickness。