Insert item before each element of a list

[Terry Reedy]

On 10/8/2012 3:28 PM, mooremathewl at gmail.com wrote:
> What's the best way to accomplish this?  Am I over-complicating it?  My gut feeling is there is a better way than the following:
>
>>>> import itertools
>>>> x = [1, 2, 3]
>>>> y = list(itertools.chain.from_iterable(('insertme', x[i]) for i in range(len(x))))
>>>> y
> ['insertme', 1, 'insertme', 2, 'insertme', 3]

The straightforward, crystal-clear, old-fashioned way

 >>> lst = []
 >>> for item in [1,2,3]:
	lst.append('insert me')
	lst.append(item)

 >>> lst
['insert me', 1, 'insert me', 2, 'insert me', 3]

Paul Rubin's list(gfunc(prefix, lst)) is similar in execution.

-- 
Terry Jan Reedy