Removing empty elements from an array

Question

1.80/5 (2 votes)

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Hi there
I Have

string[] myArray=new []{"1","2","3",""};

How can i convert/Format myArray to Look Like

string[] myArray=new []{"1","2","3"};

In other works, how can i programmatically remove the last empty entry

I am assuming that i don't know the index of the empty entry.

Thanks in advance

Martin

Posted 22-Jan-12 2:53am

katumbamartin

Updated 19-Mar-19 19:37pm

Michel [mjbohn]

v2

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Comments

BillWoodruff 22-Jan-12 10:53am

Is it absolutely essential you must use an array of strings here ?

Sergey Alexandrovich Kryukov 22-Jan-12 17:35pm

You are right if you mean it does not have to be an array -- could be too expensive in terms of performance.
That's why I added my answer, please see.
--SA

3 solutions

Solution 4

you can do this easy ans simple way

myArray = myArray.Where(x => !string.IsNullOrEmpty(x)).ToArray();

Posted 19-Mar-19 19:37pm

Member 14188764

Comments

Richard Deeming 21-Mar-19 11:17am

It might be simpler, but it will have significantly worse performance than solution 1 for large arrays.

Both ToList and ToArray have optimizations in place when the input implements ICollection<T>. But the sequence returned from Where doesn't implement ICollection<T>, so ToArray has to start with an array of 4 elements; each time it reaches the end, it creates a new array twice the size, and copies the old array to it; and finally, it has to create another new array of the correct size, and copy the elements to that.

Member 14363752 11-May-19 10:28am

I had to join Code Project just to commend you!

I have a very large, variable in size, string array, that is written to a file in a direct deposit banking project. I now use your solution as an extra error handling mechanism.
Thanks.

Solution 3

I would advise you to review your design taking into account the inherent cost of removal or insertion of an element from/into the array. This is the same as creation of a brand new array and making a copy of all data. The performance can suffer too much. Using a list as a temporary object won't solve the problem.

So, consider using containers in first place. You can use, say System.Collections.Generic.List<>, please see http://msdn.microsoft.com/en-us/library/system.collections.generic.aspx[^].

—SA

Posted 22-Jan-12 11:34am

Sergey Alexandrovich Kryukov

v2

Comments

Amir Mahfoozi 23-Jan-12 0:32am

+5

Sergey Alexandrovich Kryukov 23-Jan-12 0:54am

Thank you, Amir.
--SA

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OriginalGriff · Accepted Answer · 2012-01-22T03:24:00

Solution 2

C# doesn'ty have a direct way to do that, but... you could try:

C#

string[] x = new string[] { "1", "", "2", "", "3", "4" };
List<string> y = x.ToList<string>();
y.RemoveAll(p => string.IsNullOrEmpty(p));
x = y.ToArray()

Posted 22-Jan-12 3:24am

OriginalGriff

Comments

Sergey Alexandrovich Kryukov 22-Jan-12 17:30pm

Simple compact way. but the performance toll of using array can be a problem.
This is the same as creation of a brand new array and copying of all the remaining data.

OP might need to think about using collections.
My 5 anyway.

--SA

Sergey Alexandrovich Kryukov 22-Jan-12 17:34pm

So, I added an alternative answer...
--SA