Difference between array, arraylist, List, Hashtable, Dictionary and SortedList in c#

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Basic difference is that arrays are of fixed size. Whereas an ArrayList implements the list data structure and can dynamically grow. While arrays would be more performance that a list, a list would be far more flexible since you don't need to know the required size initially. Array - represents an old-school memory array - kind of like a alias for a normal type[] array. Can enumerate. Can't grow automatically. I would assume very fast insertion, retrieve and speed. ArrayList - automatically growing array. Adds more overhead. Can enum., probably slower than a normal array but still pretty fast. These are used a lot in .NET List - one of my favorites - can be used with generics, so you can have a strongly typed array, e.g. List . Other than that, acts very much like ArrayList. Hashtable - plain old hashtable. O(1) to O(n) worst case. Can enumerate the value and keys properties, and do key/val pairs. Dictionary - same as above only strongly typed via generics, such a...
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Difference between DataTable.Copy() Vs. DataTable.Clone() in C#

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Two major methods of DataTable in C#, One is Copy() and the other one is Clone(). Though these two sound identical but there are huge differences between these two.

There are two things to copy or clone of a DataTable. These are structure and data. Copy and Clone are playing with these two.
Let us create a DataTable first.

DataTable dt = new DataTable();
dt.Columns.Add("Id");
dt.Columns.Add("Name");
dt.Columns.Add("Email");
dt.TableName = "MasterTable";

//insert into DataTable
dt.Rows.Add("1", "Arka", "arka@gmail.com");
dt.Rows.Add("2", "Anusua", "anu@gmail.com");
dt.Rows.Add("3", "Sayantani", "sayantani@gmail.com");
 
 

DataTable.Copy() returns a DataTable with the structure and data of the DataTable.

//Creating another DataTable to copy
DataTable dt_copy = new DataTable();
dt.TableName = "CopyTable";
dt_copy = dt.Copy();

Result:
 As here, you can see the DataTable dt is being copied with the data and structure to CopyTable.

Unlike Copy(), DataTable.Clone() only returns the structure of the DataTable, not the rows or data of the DataTable.
//Creating another DataTable to clone
DataTable dt_clone = new DataTable();
dt.TableName = "CloneTable";
dt_clone = dt.Clone();
Result:


As here you can see DataTable dt is being cloned with only the structure of the MasterTable to CloneTable.
In short:
  • Copy() - For both structure and data
  • Clone() - For only structure

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