In [1]:

    

l = list('abcde')
print(l)


    

    




['a', 'b', 'c', 'd', 'e']

In [2]:

    

print(l.index('a'))


    

    




0

In [3]:

    

print(l.index('c'))


    

    




2

In [4]:

    

# print(l.index('x'))
# ValueError: 'x' is not in list


    

In [5]:

    

def my_index(l, x, default=False):
    if x in l:
        return l.index(x)
    else:
        return default


    

In [6]:

    

print(my_index(l, 'd'))


    

    




3

In [7]:

    

print(my_index(l, 'x'))


    

    




False

In [8]:

    

print(my_index(l, 'x', -1))


    

    




-1

In [9]:

    

l_dup = list('abcba')
print(l_dup)


    

    




['a', 'b', 'c', 'b', 'a']

In [10]:

    

print(l_dup.index('a'))


    

    




0

In [11]:

    

print(l_dup.index('b'))


    

    




1

In [12]:

    

print([i for i, x in enumerate(l_dup) if x == 'a'])


    

    




[0, 4]

In [13]:

    

print([i for i, x in enumerate(l_dup) if x == 'b'])


    

    




[1, 3]

In [14]:

    

print([i for i, x in enumerate(l_dup) if x == 'c'])


    

    




[2]

In [15]:

    

print([i for i, x in enumerate(l_dup) if x == 'x'])


    

    




[]

In [16]:

    

def my_index_multi(l, x):
    return [i for i, _x in enumerate(l) if _x == x]


    

In [17]:

    

print(my_index_multi(l_dup, 'a'))


    

    




[0, 4]

In [18]:

    

print(my_index_multi(l_dup, 'c'))


    

    




[2]

In [19]:

    

print(my_index_multi(l_dup, 'x'))


    

    




[]

In [20]:

    

t = tuple('abcde')
print(t)


    

    




('a', 'b', 'c', 'd', 'e')

In [21]:

    

print(t.index('a'))


    

    




0

In [22]:

    

# print(t.index('x'))
# ValueError: tuple.index(x): x not in tuple


    

In [23]:

    

print(my_index(t, 'c'))


    

    




2

In [24]:

    

print(my_index(t, 'x'))


    

    




False

In [25]:

    

t_dup = tuple('abcba')
print(t_dup)


    

    




('a', 'b', 'c', 'b', 'a')

In [26]:

    

print(my_index_multi(t_dup, 'a'))


    

    




[0, 4]

In [27]:

    

def my_index2(l, x, default=False):
    return l.index(x) if x in l else default


    

In [28]:

    

print(my_index2(l, 'd'))


    

    




3

In [29]:

    

print(my_index2(l, 'x'))


    

    




False

In [30]:

    

print(my_index2(l, 'x', -1))


    

    




-1