Using a dictionary as a source of Regex.Replace patterns in a Linq statement

Question

In C#, I know how to use Regex.Replace a Linq query to replace substrings within an input string, as shown in this code sample.

var standards = _db.MapsFromOws.AsEnumerable().Select(m => 
                 m.Section).Distinct().AsEnumerable();
var enumerable = standards as IList<string> ?? standards.ToList();

const string elaPattern1 = @"LA.\d{1,2}-\d{1,2}.(\d{1,2}).([A-z]{1,2}).(\d{1,2})";
const string elaReplace1 = "$1.$2.$3";

var ela1 = enumerable
    .AsEnumerable()
    .Select(
        m =>
            new TranslationSelectModel
            {
                Section = m,
                /* If m is a match to elaPattern1 then replace else m*/
                Translation = Regex.Replace(m, elaPattern1, elaReplace1)
            })
    .OrderBy(m => m.Section).AsEnumerable();

This works well if there is only one pattern I need to replace, but what if I have to apply a set of pattern-replacements in the same list?

I had an idea of using a Dictionary<string,string> as a source of Regex patterns and replacement string. For example,

var regexPatternDictionary = new Dictionary<string, string>()
{
  {@"LA.\d{1,2}-\d{1,2}.(\d{1,2}).([A-z]{1,2}).(\d{1,2})","$1.$2.$3"},
  {@"MA.9-12.HS.([A-z])-([A-z]{0,3}).([A-z]).(\d)(.[A-z])*","HS.$1-$2.$3.$4$5"}
};

My question is how I would be able to use Regex.Replace() so that it matches each item in the enumerable to the regular expression dictionary instead of a single string variable?

The algorithm I'm seeing in my mind is:

For each item in enumerable
- If item is a match to a dictionary, then apply replacement
Loop to next item

Roland Buergi · Accepted Answer · 2017-01-25 22:33:41Z

2

Not sure if I understand your problem 100%, but try something like this:

var result = enumerable.Select(x => replaceDictionary
                                   .Aggregate(x, (y,z) => Regex.Replace(y, z.Key, z.Value))
                       .ToArray()

answered Jan 25, 2017 at 22:33

Roland Buergi

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2 Comments

RandomHandle Over a year ago

It's a good hint. The Debug output shows that produces a translation. I need to present the input as field 1 and the translation as field 2. Trying to work that out on my side.

RandomHandle Over a year ago

Here's what did the job:

var vm = enumerable                 .Select(x => new TranslationSelectModel {Section=x, Translation=regexPatternDictionary.Aggregate(x, (y, z)                     => Regex.Replace(y, z.Key, z.Value))})                     .AsEnumerable();

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