Increase All Of A Lists Values By An Increment

I think I'm having a idiot moment, I have a list and I need to add 170 to each number list1[1,2,3,4,5,6,7,8......] list2[171,172,173......]

Solution 1:

Specific answer

With list comprehensions:

In [2]: list1 = [1,2,3,4,5,6]

In [3]: [x+170 for x in list1]
Out[3]: [171, 172, 173, 174, 175, 176]

With map:

In[5]: map(lambda x: x+170, list1)
Out[5]: [171, 172, 173, 174, 175, 176]

Turns out that the list comprehension is twice as fast:

$ python -m timeit 'list1=[1,2,3,4,5,6]' '[x+170forxin list1]'
1000000 loops, best of 3: 0.793 usec per loop
$ python -m timeit 'list1=[1,2,3,4,5,6]' 'map(lambda x: x+170, list1)'
1000000 loops, best of 3: 1.74 usec per loop

Some bench-marking

After @mgilson posted the comment about numpy, I wondered how it stacked up. I found that for lists shorter than 50 or so elements, list comprehensions are faster, but numpy is faster beyond that.

Solution 2:

incremented_list = [x+170 for x in original_list]