Python list's +, + =, and extend operations

The latter is said to have a slightly better performance when the list is large.

A test was then made:

Import Timedef Time_cost (func):    def _time_cost (*args,**kw):        t1=time.time ()        func (*args,**kw)        t2= Time.time ()        return t2-t1    return _time_cost@time_costdef test_add (list_a,huge_list_b):    return list_a+ Huge_list_b@time_costdef test_extend (list_a,huge_list_b):    return List_a.extend (huge_list_b) if __name__== ' __ main__ ':    print '-----big list test-------------'    a=[1]*1000    b=[' a ']* (10**8)    print ' Add cost:%s Seconds '%test_add (A, b)    print ' Extend cost:%s seconds '%test_extend (A, b)    print '-----small list Test-------------'    a=[1]*1000    b=[' a ']* (10**2)    print ' Add cost:%s seconds '%test_add (A, b)    print ' Extend cost:%s seconds '%test_extend (A, B)

　　

　　

My machine is win7,64bit,6g memory, i3 CPU, the result is as follows:

-----Big list Test-------------add cost:1.30500006676 secondsextend cost:0.591000080109 seconds-----Small List Test-------------Add cost:0.0 secondsextend cost:0.0 seconds

　　

When B is 10^8 length, extend consumes almost half the time it takes to operate.

At the 1000-length level, the difference is small. Almost the same.

+ = equals to extend, as follows:

Import Timedef Time_cost (func):    def _time_cost (*args,**kw):        t1=time.time ()        func (*args,**kw)        t2= Time.time ()        return t2-t1    return _time_cost@time_costdef test_add (list_a,huge_list_b):    List_a+=huge_ List_b    return list_a@time_costdef test_extend (list_a,huge_list_b):    return List_a.extend (huge_list_b) if __ name__== ' __main__ ':    print '-----big list test-------------'    a=[1]*1000    b=[' a ']* (10**8)    a2=[1]* Print    ' + = cost:%s seconds '%test_add (A, b)    print ' Extend cost:%s seconds '%test_extend (a2,b)

Output:

-----Big list Test-------------+ = cost:0.506999969482 secondsextend cost:0.510999917984 seconds

　　

Python list's +, + =, and extend operations