在if循环中需要帮助

Question

我是python编码的新手，我的代码中确实包含以下简单的 list 。

Marks = [82,70,60,50,40,30]

现在我的要求是，我想在输出中获得另一列，称为结果，如下所示

那么如何使用 if 和 else 来实现我想要的输出

if Marks > 80 print 'Distinction'
if Marks >60 and Marks <= 70 print 'Grade A'
if Marks >50 and Marks <= 60 print 'Grade B'
if Marks >40 and Marks <= 50 print 'Grade C'
else print 'Good for Nothing'

Answer 1

这对np.where是一件好事：

df['Result'] = 'Good for Nothing'
df['Result'] = np.where((df['Marks'] > 80), 'Distinction', df['Result'])
df['Result'] = np.where((df['Marks'] > 60) & (df['Marks'] <= 70), 'Grade A', df['Result'])
df['Result'] = np.where((df['Marks'] > 50) & (df['Marks'] <= 60), 'Grade B', df['Result'])
df['Result'] = np.where((df['Marks'] > 40) & (df['Marks'] <= 50), 'Grade C', df['Result'])

Answer 2

在Python3中尝试类似的方法

Marks = [82,70,60,50,40,30]

for i in Marks: 
    if i > 80:
        print('Distinction')
    elif i >60 and i <= 70:
        print('Grade A')
    elif i >50 and i <= 60:
        print('Grade B')
    elif i >40 and i <= 50:
        print('Grade C')
    else:
        print('Good for Nothing')

Answer 3

Marks = [82,70,60,50,40,30]
df = pd.DataFrame({'Marks' : Marks})
print(df)

def a(b):
if b['Marks'] > 80:
    return 'Distinction'
elif b['Marks'] > 69:
    return 'Grade A'
elif b['Marks'] > 59:
    return 'Grade B'
elif b['Marks'] > 49:
    return 'Grade C'
else:
    return 'Good for Nothing'

df['Result'] = df.apply(a, axis=1)
print(df)