The easiest way to separate substrings from a line string

Ruby
1

I have working on tag system and There is information like this

“important urgent project 2009”

i want to seperate into word, one word at the time is okay

What is the easiest way to separate those string word by word, space
between each word might has more than 1.

My idea is to use loop to check character by character that it is space
or not, and then cut the part, but i thought it might have easier way
that i don’t know

Thank you in advance

2

Hi –

On Thu, 9 Jul 2009, Sarawut Poaitwinyu wrote:

or not, and then cut the part, but i thought it might have easier way
that i don’t know

words = string.split

When you call split with no argument, it splits on whitespace
(including more than one character).

David

3

David A. Black wrote:

Hi –

On Thu, 9 Jul 2009, Sarawut Poaitwinyu wrote:

or not, and then cut the part, but i thought it might have easier way
that i don’t know

words = string.split

When you call split with no argument, it splits on whitespace
(including more than one character).

David

   Thank you , i will try
4

2009/7/9 David A. Black [email protected]:

What is the easiest way to separate those string word by word, space
between each word might has more than 1.

My idea is to use loop to check character by character that it is space
or not, and then cut the part, but i thought it might have easier way
that i don’t know

words = string.split

When you call split with no argument, it splits on whitespace
(including more than one character).

I am more like the “positive” guy - meaning explicitly defining what I
want returned. I would do

words = string.scan /\w+/

That way dot, question mark and other signs won’t hurt. It may not
make a difference but it’s probably good to see different approaches.

Kind regards

robert

5

Hi –

On Fri, 10 Jul 2009, Robert K. wrote:

(including more than one character).

I am more like the “positive” guy - meaning explicitly defining what I
want returned. I would do

words = string.scan /\w+/

That way dot, question mark and other signs won’t hurt. It may not
make a difference but it’s probably good to see different approaches.

string.split does explicitly define what I want back; it’s just
something different from what you want back :slight_smile: It depends exactly how
you define “word”. I was assuming it was /\S+/ but it may indeed be
/\w+/ (or maybe /[^\W\d_]+/ or something).

David

6

2009/7/9 David A. Black [email protected]:

On Fri, 10 Jul 2009, Robert K. wrote:

2009/7/9 David A. Black [email protected]:

On Thu, 9 Jul 2009, Sarawut Poaitwinyu wrote:

That way dot, question mark and other signs won’t hurt. It may not
make a difference but it’s probably good to see different approaches.

string.split does explicitly define what I want back; it’s just
something different from what you want back :slight_smile:

That’s true. I just wanted to make the point that there are these two
major approaches: define positively what you want in your result or
define it ex negativo, i.e. state what you want to use as separator.

The whole point is that both approaches may behave identical with the
original set of test data but will exhibit different behavior as soon
as the input changes. If you use #split, you might get something you
did not want in the first place. With #scan you won’t notice - which
could be bad as well.

The super safe variant would be to first do a match on the whole
string to ensure it does contain expected data only and fail if not.
After that it does not matter any more what extraction method one
uses.

It depends exactly how
you define “word”. I was assuming it was /\S+/ but it may indeed be
/\w+/ (or maybe /[^\W\d_]+/ or something).

Absolutely.

Kind regards

robert

7

Thank you for everyone again, it seems that you guys discussed sort of
regular expression that i didn’t understand but thank you for it anyone,
i will try to research about it later

8

Hi –

On Mon, 13 Jul 2009, Dave B. wrote:

Moving off-topic from the thread, but David Black wrote:

… /\w+/ (or maybe /[^\W\d_]+/ or something).

Do people actually say /[^\W\d_]/ instead of /[a-z]/i? The latter is
much easier for me to read. Does the former include non-latin
word-characters?

Yes:

s = “\u00e9”
=> “é”

/\w/.match(s)
=> #<MatchData “é”>

/[a-z]/.match(s)
=> nil

Another choice would be:

/[[:alpha:]]/

which I believe would do the same thing that my character class did
(unless there are some exclusions, inclusions, or edge cases I’m not
remembering).

David

9

Moving off-topic from the thread, but David Black wrote:

… /\w+/ (or maybe /[^\W\d_]+/ or something).

Do people actually say /[^\W\d_]/ instead of /[a-z]/i? The latter is
much easier for me to read. Does the former include non-latin
word-characters?

Cheers,
Dave B.