Map Vs List Comprehension

Case 1. Map Vs List comprehension for user defined function

:~ sadatravu$ python -mtimeit -s'xs = xrange(10)' 'def ch(x): return x+10' 'map(ch ,xs)'

1000000 loops, best of 3: 1.3 usec per loop

:~ sadatravu$ python -mtimeit -s'xs = xrange(10)' 'def ch(x): return x+10' '[ch(x) for x in xs]'

1000000 loops, best of 3: 1.39 usec per loop

Case 2. Map Vs List comprehension for inbuilt function

:~ sadatravu$ python -mtimeit -s'xs = xrange(10)'  'map(hex,xs)'

1000000 loops, best of 3: 0.926 usec per loop

:~ sadatravu$ python -mtimeit -s'xs = xrange(10)'  '[hex(x) for x in xs]'

1000000 loops, best of 3: 1.14 usec per loop

Case 3. Map Vs List comprehension for function built by lambda

python -mtimeit -s'xs = xrange(10)'  'map(lambda x: x+10,xs)'

1000000 loops, best of 3: 1.29 usec per loop

python -mtimeit -s'xs = xrange(10)'  '[lambda x: x+10 for x in xs]'

1000000 loops, best of 3: 0.958 usec per loop

Time taken by map function is lesser in Case1&2, whereas higher in Case3

                                                        Map                     ListComprehension

1. User defined function                  1.3 usec                      1.39 usec

2. Inbuilt function                           0.926 usec                  1.14 usec   

3. function built by lambda            1.29 usec                    0.958 usec