Idiom for "last word in a string"

[Grant Edwards]

I recently ran across this construct for grabbing the last
(whitespace delimited) word in a string:

s.rsplit(None,1)[1]

It was somewhat obvious from the context what it was supposed
to do, but it took a bit of Googling to figure out exactly what
was going on.

When I want the last word in a string, I've always done this:

s.split()[-1]

I was wondering what the advantage of the rsplit(None,1)[1]
approach would be other than inducing people to learn about the
maxsplit argument that is accepted by the split() methods?

 

[akonsu]

I recently ran across this construct for grabbing the last
(whitespace delimited) word in a string:

   s.rsplit(None,1)[1]

It was somewhat obvious from the context what it was supposed
to do, but it took a bit of Googling to figure out exactly what
was going on.

When I want the last word in a string, I've always done this:

   s.split()[-1]

I was wondering what the advantage of the rsplit(None,1)[1]
approach would be other than inducing people to learn about the
maxsplit argument that is accepted by the split() methods?

hello,
perhaps rsplit generates as many elements in the list as absolutely
necesary compared to the whole list returned by split()?
konstantin

 

[Christos Trochalakis]

At Wed, 23 Sep 2009 18:47:05 +0000 (UTC),

I recently ran across this construct for grabbing the last
(whitespace delimited) word in a string:

s.rsplit(None,1)[1]

It was somewhat obvious from the context what it was supposed
to do, but it took a bit of Googling to figure out exactly what
was going on.

When I want the last word in a string, I've always done this:

s.split()[-1]

I was wondering what the advantage of the rsplit(None,1)[1]
approach would be other than inducing people to learn about the
maxsplit argument that is accepted by the split() methods?

s.rsplit(None, 1) is a cheaper operation because it splits the string
*only once*.

 

[Christos Trochalakis]

At Wed, 23 Sep 2009 18:47:05 +0000 (UTC),

I recently ran across this construct for grabbing the last
(whitespace delimited) word in a string:

s.rsplit(None,1)[1]

It was somewhat obvious from the context what it was supposed
to do, but it took a bit of Googling to figure out exactly what
was going on.

When I want the last word in a string, I've always done this:

s.split()[-1]

I was wondering what the advantage of the rsplit(None,1)[1]
approach would be other than inducing people to learn about the
maxsplit argument that is accepted by the split() methods?

s.rsplit(None, 1) is a cheaper operation because it splits the string
*only once*.

 

[Christos Trochalakis]

At Wed, 23 Sep 2009 18:47:05 +0000 (UTC),

I recently ran across this construct for grabbing the last
(whitespace delimited) word in a string:

s.rsplit(None,1)[1]

It was somewhat obvious from the context what it was supposed
to do, but it took a bit of Googling to figure out exactly what
was going on.

When I want the last word in a string, I've always done this:

s.split()[-1]

I was wondering what the advantage of the rsplit(None,1)[1]
approach would be other than inducing people to learn about the
maxsplit argument that is accepted by the split() methods?

s.rsplit(None, 1) is a cheaper operation because it splits the string
*only once*.

 

[Christos Trochalakis]

At Wed, 23 Sep 2009 18:47:05 +0000 (UTC),

I recently ran across this construct for grabbing the last
(whitespace delimited) word in a string:

s.rsplit(None,1)[1]

It was somewhat obvious from the context what it was supposed
to do, but it took a bit of Googling to figure out exactly what
was going on.

When I want the last word in a string, I've always done this:

s.split()[-1]

I was wondering what the advantage of the rsplit(None,1)[1]
approach would be other than inducing people to learn about the
maxsplit argument that is accepted by the split() methods?

s.rsplit(None, 1) is a cheaper operation because it splits the string
*only once*.

 

[Peter Otten]

I recently ran across this construct for grabbing the last
(whitespace delimited) word in a string:

s.rsplit(None,1)[1]

It was somewhat obvious from the context what it was supposed
to do, but it took a bit of Googling to figure out exactly what
was going on.

When I want the last word in a string, I've always done this:

s.split()[-1]

I was wondering what the advantage of the rsplit(None,1)[1]
approach would be other than inducing people to learn about the
maxsplit argument that is accepted by the split() methods?

hello,
perhaps rsplit generates as many elements in the list as absolutely
necesary compared to the whole list returned by split()?
konstantin

Indeed, and if the string is long it has a measurable effect:

$ python -m timeit -s"s = 'oneword '*1000" "s.rsplit(None, 1)[-1]"
100000 loops, best of 3: 2.23 usec per loop
$ python -m timeit -s"s = 'oneword '*1000" "s.split()[-1]"
1000 loops, best of 3: 191 usec per loop

Peter