here is an example code
>>> array = [('The', 'Blue'),('men','Green'),('his','Red'),('beautiful','Yellow')]
>>> z = [y for (x,y) in array]
>>> l=[(z[i],z[i+1]) for i in range (len(z)-1)]
>>> l
>>> [('Blue', 'Green'), ('Green', 'Red'), ('Red', 'Yellow')]
Is there an alternative way to write this? say, maybe as a one-liner? The above code is better suited from running via a console.
Thanks all
Pulling all answers here together, this one-liner would work:
a = [('The', 'Blue'),('men','Green'),('his','Red'),('beautiful','Yellow')]
l = [(i[1],j[1]) for i,j in zip(a, a[1:])]
Result:
>>> print(l)
>>> [('Blue', 'Green'), ('Green', 'Red'), ('Red', 'Yellow')]
Just to explain, the zip built-in function takes two or more iterables and yields a tuple with the current item for each iterable, until the end of the iterable with the smallest length is reached.
You can use zip function :
>>> array = [('The', 'Blue'),('men','Green'),('his','Red'),('beautiful','Yellow')]
>>> z = [y for (x,y) in array]
>>> zip(z,z[1:])
[('Blue', 'Green'), ('Green', 'Red'), ('Red', 'Yellow')]
This can be done as a one-liner, but it looks pretty ugly.
a = [('The', 'Blue'),('men','Green'),('his','Red'),('beautiful','Yellow')]
l = zip(zip(*a)[1], zip(*a)[1][1:])
Two lines is much better:
colors = zip(*a)[1]
l = zip(colors, colors[1:])
FWIW, you can drop the parentheses in
z = [y for (x,y) in array]
And since you're not using x it's common to replace it with underscore:
z = [y for _,y in array]
array = [('The', 'Blue'),('men','Green'),('his','Red'),('beautiful','Yellow')]
result = [(array[i][1], array[i+1][1]) for i in xrange(len(array)-1)]
print result
Yields:
[('Blue', 'Green'), ('Green', 'Red'), ('Red', 'Yellow')]
