Split String Based On An Arbitrary Array in C#

Question

I want to split the 'tmpstr' members based on a 'tmpnumstr' members. here is my temporary solution , but i am looking for the general solution for arbitrary 'tmpstr' and 'tmpnumstr'.

string tmpstr = "New,Open,Exit,Copy,Cut,Paste,Help,About,"; 
string tmpnumstr = "3,3,2,"; // string of numbers

string[] tmpstrArray = tmpstr.TrimEnd(',').Split(',');

for (int i = 0; i < 3; i++)
{
    textBox1.Text += tmpstrArray[i] + @",";
}
textBox1.Text += Environment.NewLine;
for (int i = 3; i < 6; i++)
{
    textBox1.Text += tmpstrArray[i] + @",";
}
textBox1.Text += Environment.NewLine;
for (int i = 6; i < 8; i++)
{
    textBox1.Text += tmpstrArray[i] + @",";
}
textBox1.Text += Environment.NewLine;

The output is ==>
New,Open,Exit,
Copy,Cut,Paste,
Help,About,

user447356 · Accepted Answer · 2016-03-13 08:41:48Z

5

Sounds like you want to split the raw string to several arrays, based on dynamic input?

In such case, you should split the words to a flat list first, then use combination of .Skip() and .Take() to split it further to sub groups.

Sample code using your existing code as its base:

string rawWords = "New,Open,Exit,Copy,Cut,Paste,Help,About,";
string rawGroupCounts = "3,3,2,"; // string of numbers
List<int> groupCounts = rawGroupCounts.Split(new char[] { ',' }, 
    StringSplitOptions.RemoveEmptyEntries).
    ToList().ConvertAll(rawValue => Int32.Parse(rawValue));
List<string> words = rawWords.Split(new char[] { ',' }, 
    StringSplitOptions.RemoveEmptyEntries).ToList();
List<List<string>> wordGroups = new List<List<string>>();
if (groupCounts.Count > 0)
{
    int skipCounter = 0;
    groupCounts.ForEach(count =>
    {
        wordGroups.Add(words.Skip(skipCounter).Take(count).ToList());
        skipCounter += count;
    });
}
textBox1.Text = string.Join(Environment.NewLine, 
    wordGroups.ConvertAll(group => string.Join(", ", group)));

(I have also changed the variable names to have some meaning)

answered Mar 13, 2016 at 8:41

user447356

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3 Comments

BlueFlower Over a year ago

u-p-v-o-t-e for you for your nice answer

user447356 Over a year ago

Thanks, guess it means it's working for you. Cheers!

ehh Over a year ago

very nice solution

shreyans800755 · Accepted Answer · 2016-03-14 17:29:29Z

1

I believe this should do it.

string tmpstr = "New,Open,Exit,Copy,Cut,Paste,Help,About,"; 
string tmpnumstr = "3,3,2,"; // string of numbers

string[] tmpstrArray = tmpstr.TrimEnd(',').Split(',');
int[] tmpnumstrArray = tmpnumstr.TrimEnd(',').Split(',').Select(x => int.Parse(x)).ToArray();       //To convert tmpnumstr to integer array

for(int i=1;i<tmpnumstrArray.Length;i++)
    tmpnumstrArray[i] += tmpnumstrArray[i - 1];

for(int i = 0, k = 0;i < tmpnumstrArray[tmpnumstrArray.Length - 1];i++)
{
    if(i == tmpnumstrArray[k])
    {
        textBox1.Text += Environment.NewLine;
        k++;
    }
    textBox1.Text += tmpstrArray[i] + @",";
}
textBox1.Text += Environment.NewLine;

edited Mar 14, 2016 at 17:29

answered Mar 13, 2016 at 8:37

shreyans800755

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1 Comment

BlueFlower Over a year ago

u-p-v-o-t-e for you for your answer but you need to fix ' Cannot implicitly convert type 'System.Collections.Generic.IEnumerable<int>' to 'int[]'. An explicit conversion exists (are you missing a cast?) ' in your answer :)

BatteryBackupUnit · Accepted Answer · 2016-03-13 14:54:12Z

0

Given the following helper classes for "sugar":

public class BatchingProcessor<T>
{
    private readonly IEnumerator<T> enumerator;

    public BatchingProcessor(IEnumerable<T> enumerable)
    {
        this.enumerator = enumerable.GetEnumerator();
    }

    public Batch<T> Take(int count)
    {
        var values = this.TakeUntilEndIsReached(count).ToArray();
        return new Batch<T>(values, count);
    }

    private IEnumerable<T> TakeUntilEndIsReached(int count)
    {
        for (int i = 0; i < count; i++)
        {
            if (enumerator.MoveNext())
            {
                yield return enumerator.Current;
            }
            else
            {
                break;
            }
        }
    }
}

public class Batch<T>
{
    private readonly T[] values;
    private readonly int batchSize;

    public Batch(T[] values, int batchSize)
    {
        this.values = values;
        this.batchSize = batchSize;
    }

    public T[] Values => this.values;

    public int BatchSize => this.batchSize;

    public bool EndReached => this.values.Length < this.batchSize;
}

We can write:

string tmpstr = "New,Open,Exit,Copy,Cut,Paste,Help,About,";
string tmpnumstr = "3,3,2,"; // string of numbers;

string[] items = tmpstr.Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
int[] itemSequence = tmpnumstr
    .Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries)
    .Select(x => Convert.ToInt32(x))
    .ToArray();

var sb = new StringBuilder();
var batchingProcessor = new BatchingProcessor<string>(items);
foreach (int itemCount in itemSequence)
{
    var batch = batchingProcessor.Take(itemCount);

    foreach (string item in batch.Values)
    {
        sb.Append(item);
        sb.Append(",");
    }
    sb.AppendLine();

    if (batch.EndReached)
    {
        // tmpnumstr specifies more strings than tmpstr contains.
        break;
    }
}

textBox1.Text = sb.ToString();

i've tested that it results in exactly the same string as your original code:

string expectedString = @"New,Open,Exit,
Copy,Cut,Paste,
Help,About,
";

sb.ToString().Should().Be(expectedString);

Now, if you're sure that the item count and group specification matches, we don't need to check for that and can do:

string tmpstr = "New,Open,Exit,Copy,Cut,Paste,Help,About,";
string tmpnumstr = "3,3,2,"; // string of numbers;

string[] items = tmpstr.Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
int[] itemSequence = tmpnumstr
    .Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries)
    .Select(x => Convert.ToInt32(x))
    .ToArray();

var batchingProcessor = new BatchingProcessor<string>(items);

var batches = itemSequence
    .Select(itemCount => batchingProcessor.Take(itemCount))
    .Select(batch => string.Join(",", batch.Values))
    .ToArray();

textBox1.Text = string.Join("," + Environment.NewLine, batches);

edited Mar 13, 2016 at 14:54

answered Mar 13, 2016 at 8:56

BatteryBackupUnit

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4 Comments

user447356 Over a year ago

All of this just to avoid using list of lists? Or is there something else I'm missing?

BatteryBackupUnit Over a year ago

@ShadowWizard The BatchProcessor<T> is a helper class that i use from time to time. In my opinion it allows to write more concise code. I thought of writing a Skip(), Take() solution first but if there's a large dataset this requires a lot of enumerator-processing (one's skipping the same elements many times).

user447356 Over a year ago

True, but it looks like using a 5 kilo hammer to put a small nail into the wall. :-)

BatteryBackupUnit Over a year ago

@ShadowWizard true if you never ever need the BatchProcessor<T> again then it's quite a lot of code for that problem. However i believe clean-code is worth something, too ;-) Also, if i see this right, the currently accepted solutions cannot handle not-matching arrays "gracefully". Now, granted, i'm a big believer in "fail fast", too, so hiding issues is a decision which should not be taken lightly...

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