In [1]:

    

l = ['Banana', 'Alice', 'Apple', 'Bob']


    

In [2]:

    

print(sorted(l))


    

    




['Alice', 'Apple', 'Banana', 'Bob']

In [3]:

    

print(sorted(l, reverse=True))


    

    




['Bob', 'Banana', 'Apple', 'Alice']

In [4]:

    

l_order = ['Alice', 'Bob', 'Apple', 'Banana']


    

In [5]:

    

print(sorted(l, key=l_order.index))


    

    




['Alice', 'Bob', 'Apple', 'Banana']

In [6]:

    

print(l)


    

    




['Banana', 'Alice', 'Apple', 'Bob']

In [7]:

    

print([l_order.index(s) for s in l])


    

    




[3, 0, 2, 1]

In [8]:

    

print(sorted(l, key=l_order.index))


    

    




['Alice', 'Bob', 'Apple', 'Banana']

In [9]:

    

d_order = {'Alice': 0, 'Bob': 1, 'Apple': 2, 'Banana': 3}


    

In [10]:

    

print(sorted(l, key=lambda x: d_order[x]))


    

    




['Alice', 'Bob', 'Apple', 'Banana']

In [11]:

    

l = ['Banana', 'Alice', 'Apple', 'Bob', 'xxx']
l_order = ['Alice', 'Bob', 'Apple', 'Banana']


    

In [12]:

    

# print(sorted(l, key=l_order.index))
# ValueError: 'xxx' is not in list


    

In [13]:

    

print(sorted(l, key=lambda x: l_order.index(x) if x in l_order else -1))


    

    




['xxx', 'Alice', 'Bob', 'Apple', 'Banana']

In [14]:

    

print(sorted(l, key=lambda x: l_order.index(x) if x in l_order else float('inf')))


    

    




['Alice', 'Bob', 'Apple', 'Banana', 'xxx']

In [15]:

    

def my_index(x):
    l_order = ['Alice', 'Bob', 'Apple', 'Banana']
    return l_order.index(x) if x in l_order else -1


    

In [16]:

    

print(sorted(l, key=my_index))


    

    




['xxx', 'Alice', 'Bob', 'Apple', 'Banana']

In [17]:

    

l = ['Banana', 'Alice', 'Apple', 'Bob']
l_order = ['Alice', 'Bob', 'Apple', 'Banana', 'xxx']


    

In [18]:

    

print(sorted(l, key=l_order.index))


    

    




['Alice', 'Bob', 'Apple', 'Banana']

In [19]:

    

l = ['Banana', 'Alice', 'Apple', 'Bob', 'xxx']
d_order = {'Alice': 0, 'Bob': 1, 'Apple': 2, 'Banana': 3}


    

In [20]:

    

# print(sorted(l, key=lambda x: d_order[x]))
# KeyError: 'xxx'


    

In [21]:

    

print(sorted(l, key=lambda x: d_order.get(x, -1)))


    

    




['xxx', 'Alice', 'Bob', 'Apple', 'Banana']

In [22]:

    

print(sorted(l, key=lambda x: d_order.get(x, float('inf'))))


    

    




['Alice', 'Bob', 'Apple', 'Banana', 'xxx']

In [23]:

    

l = ['Banana', 'Alice', 'Apple', 'Bob']
d_order = {'Alice': 0, 'Bob': 1, 'Apple': 2, 'Banana': 3, 'xxx': 4}


    

In [24]:

    

print(sorted(l, key=lambda x: d_order[x]))


    

    




['Alice', 'Bob', 'Apple', 'Banana']