C# Useful Array.Methods()

Array.IndexOf()

• returns index of item inside array
• params: (array, value to find)

Example

var colors = new[] { "red", "green", "blue" };

var result = Array.IndexOf(colors, "red");
WriteLine(result); // 0 

Array.Exists()

• returns a boolean if conditions are met
• params: (array, conditions)

Example

var colors = new[] { "red", "green", "blue" };

var result = Array.Exists(colors, color => color.Contains("green"));
WriteLine(result); // true

Array.Find()

• returns the first item to meet a condition
• params: (array, condition)

Example

var colors = new[] { "red", "green", "blue" };

var result = Array.Find(colors, color => color.Contains("green"));
WriteLine(result); // "green"

Array.FindLast()

• Starts search from the LAST index
• returns the first item to meet a condition
• params: (array, condition)

Array.FindIndex()

• returns the index of the element that meets the condition
• params: (array, condition)

Example

var colors = new[] { "red", "green", "blue" };

var result = Array.FindIndex(colors, color => color.Contains("green"));
WriteLine(result); // 1

Array.FindAll()

• returns array of all conditions met
• params: (array, condition)

Example

var colors = new[] { "red", "green", "blue" };

var result = Array.FindAll(colors, color => color.Contains("r"));

foreach (var color in result) 
{ 
  WriteLine(color); 
}
// "red"
// "green"

Array.Reverse()

• returns array with all elements in reverse order
• params: (array)

Example

var colors = new[] { "red", "green", "blue" };

var result = Array.Reverse(colors);

foreach (var color in result) 
{ 
  WriteLine(color); 
}
// "blue"
// "green"
// "red"

Array.Copy()

• copy elements to a new array
• can specify how many elements to copy
• params: (originalArray, copy, numberOfElementsToCopy)

Example

var colors = new[] { "red", "green", "blue" };
var colors2 = new string[colors.length];

Array.Copy(colors, colors2, 2);

foreach (var color in colors2) 
{ 
  WriteLine(color); 
}
// "red"
// "green"

Array.Sort()

• sort the elements of an array
• params: (array)

Example

var colors = new[] { "red", "green", "blue" };
Array.Sort(colors);

foreach (var color in colors) 
{ 
  WriteLine(color); 
}
// "blue"
// "green"
// "red"

Array.BinarySearch()

• search a sorted array
• returns the index of the found item
• returns -1 if nothing is found

Example

var colors = new[] { "red", "green", "blue" };
Array.Sort(colors); // "blue", "green", "red"

var index = Array.BinarySearch(colors, "green");
if (index == -1)
{
  WriteLine("not found");
}
else
{
  WriteLine(index); // 1
}