Add regex string to array

Question

I need to add a regex string to an array but I get an error like "string can't implement in string[]".

This is the code:

foreach (string ss in fileLines)
{
    filelinesclean = System.Text.RegularExpressions.Regex.Replace(ss, @"\s+", " ");
    MessageBox.Show("ok");
    System.IO.File.WriteAllLines(@"C:\Users\Public\WriteLines.txt", filelinesclean);
}

filelinesclean is a string but File.WriteAllLines takes an array of strings for its second parameter. Perhaps you meant to use File.WriteLine. — Andrew Morton
– Andrew Morton, Commented Mar 9, 2016 at 20:30
So that no-one proposes an answer which could result in running out of memory, how large is the (presumably) file from which you get fileLines? — Andrew Morton
– Andrew Morton, Commented Mar 9, 2016 at 20:38

juharr · Accepted Answer · 2016-03-09 20:44:28Z

First add the following usings so you don't need to type out the entire namespaces for everything.

using System.Text.RegularExpressions;
using System.IO;

The reason it doesn't work is because File.WriteAllLines expects a IEnumerabl<string> or a string[], but you're passing a string. Either use File.AppendAllText or just call File.WriteAllLines once after the foreach like this.

var lines = new List<string>();
foreach (string ss in fileLines)
{
    lines.Add(Regex.Replace(ss, @"\s+", " "));
}
MessageBox.Show("ok");
File.WriteAllLines(@"C:\Users\Public\WriteLines.txt", lines);

Or like this using Linq

File.WriteAllLines(
    @"C:\Users\Public\WriteLines.txt",
    fileLines.Select(ss => Regex.Replace(ss, @"\s+", " "));

But based on some of your comments you might want to do the following

File.WriteAllLines(
    @"C:\Users\Public\WriteLines.txt",
    File.ReadLines(@"InputPath")
        .Select(ss => Regex.Replace(ss, @"\s+", " "));

Because of lazy initialization that will read in each line of your input file one at a time, do the regular expression replacement then write the line out before moving to the next line. That will be scale-able if you need to run this on a very large file as it does not require the entire file to be in memory at one time.

developer033 · Accepted Answer · 2016-03-10 00:18:44Z

0

I am not sure about your requirement but it seems you are trying to use string in place of collection. This code may help.

List<string> lines = new List<string>();
foreach (string ss in fileLines)
{
   string filelinesclean = System.Text.RegularExpressions.Regex.Replace(ss, @"\s+", " ");
   lines.Add(filelinesclean);
}
System.IO.File.WriteAllLines(@"C:\Users\Public\WriteLines.txt", lines);

I have keep your code as it is and added/updated few lines.

edited Mar 10, 2016 at 0:18

developer033

25k8 gold badges85 silver badges113 bronze badges

answered Mar 9, 2016 at 20:34

Mitesh

741 silver badge7 bronze badges

1 Comment

juharr Over a year ago

There's no point in overwriting the file on each iteration of the loop.

Collectives™ on Stack Overflow

Add regex string to array

2 Answers 2

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related