How to extract words from structured string?

Question

I have the following string:

"select model (field1, field2, field3, ...)"

And I would like to write something that extracts the words where model and the fields are.

So for instance:

select Car (door, wheel, antenna)

Method 1 returns Car. Method 2 returns List/Array {door, wheel, antenna}

So in other words, I am looking for extractModel() and extractFields().

I feel like RegEx is needed here, but I don't know how to tackle this problem.

Do you mean that "select model (field1, field2, ...)" is your source string and you're trying to capture values in the string? — Rikki Gibson, Sep 05 '15 at 16:15
Is the input string _always_ in the _exact_ format "`select $object ($field[, $field[, ...]])`"? If so, have you tried building a regex that captures that? — CodeCaster, Sep 05 '15 at 16:18

rbm · Accepted Answer · 2015-09-05T16:34:41.887

3

This should work:

var m = "select Car (door, wheel, antenna)";
Regex r = new Regex(@"select\s+(.*)\s+\((.*)\)");
var model = r.Match(m).Groups[1].Value;
// untrimmmed:
// var fields = r.Match(m).Groups[2].Value.Split(',');
// trimmed:
var fields = r.Match(m).Groups[2].Value.Split(',').Select(s => s.Trim()).ToArray();

edited Sep 05 '15 at 16:34

answered Sep 05 '15 at 16:18

rbm

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I'd add a `.Select(Trim).ToArray()` to trim the input. – CodeCaster Sep 05 '15 at 16:20
A few points on that `.Select(_ => _.Trim());`: [`_` is the syntax for an ignored parameter](http://stackoverflow.com/questions/424775/is-there-a-better-way-to-express-a-parameterless-lambda-than) (`s` would suffice), you can abbreviate it to `Select(Trim)` and you'd want this result materialized (`.ToList()` or `.ToArray()`) as you'll probably iterate it somewhere anyhow, and this would make multiple enumerations or other operations safe and possible. So please make it `.Select(Trim).ToList()` (or `ToArray()`) and you have my upvote back. ;-) – CodeCaster Sep 05 '15 at 16:22
1

I use '_' routinely - a habbit. Agree with `ToArray()` - added. But the `Select(Trim)` does not work. – rbm Sep 05 '15 at 16:36

score 0 · Answer 2 · answered Sep 05 '15 at 16:24

0

Another direction to go:

select (\S*) \(([^)]*)

The second match group is a comma separated list, and you split on it.

http://rubular.com/r/ByLODRGVdy

answered Sep 05 '15 at 16:24

Rikki Gibson

4,136
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How to extract words from structured string?

2 Answers2