VB functions for filtering, transforming, aggregating, and sorting data in apps, including Where, Select, Aggregate, GroupBy, and more.

This page contains VB expressions that you may find useful while building your app.

We grouped several of these functions in a public app, so you can try out them out and see how they behave.

The Where() function returns a zero-based array containing a subset of a string array based on a specified filter criteria.

Assume you have a variable called words defined as List(Of String) = {"apple", "banana", "cherry", "date"}.

To get the list of words that contain the letter "a", apply the Where() function as follows:

The output is {"apple", "banana", "date"}.

The Select() function creates a new array that contains the results of applying a lambda expression to each element in the source array.

Assume you have a variable called numbers defined as Integer() = {1, 2, 3, 4, 5}.

To get the list of numbers multiplied by themselves, apply the Select() function as follows:

The output is {1, 4, 9, 16, 25}.

The Aggregate() function performs calculations over all the elements in an array and returns a single value. This function can be useful in aggregating multiple values inside a column.

Assume you have a variable called numbers defined as Integer() = {1, 2, 3, 4, 5}.

To get the sum of all the numbers in the array, apply the Aggregate() function as follows:

The output is 15.

The GroupBy() function groups elements in a sequence by a key selector function.

Assume you have a variable called words defined as String() = {"apple", "banana", "cherry", "date"}.

To group the words by the first letter, which is the key selector function, apply the GroupBy() function as follows:

The output is { {"a", "apple", "date"}, {"b", "banana"}, {"c", "cherry"} }.

The OrderBy() and OrderByDescending() functions sort elements in a sequence based on a key selector function.

Assume you have a variable called words defined as String() = {"apple", "banana", "cherry", "date"}.

To order the words by their length, which is the key selector function, apply the OrderBy() function as follows:

The output is {"date", "apple", "cherry", "banana"}.

The Join() function combines elements in two sequences based on a key selector function.

Assume you have two variables:

To combine the elements in the first sequence with the elements in the second sequence, apply the Join() function as follows:

The output is {"John: 25", "Jane: 30", "Joe: 35"}.

The First() function returns the first element in a sequence that satisfies a specified condition.

Assume you have a variable called numbers defined as Integer() = {1, 2, 3, 4, 5}.

To get the first even number in the sequence, apply the First() function as follows:

The output is 2.

The FirstOrDefault() function returns the first element, or a default value if no element satisfies the condition.

Assume you have a variable called numbers defined as Integer() = {1, 2, 3, 4, 5}.

To get the first odd number in the sequence, apply the FirstOrDefault() function as follows:

The output is 1.

The Last() function returns the last element in a sequence that satisfies a specified condition.

Assume you have a variable called numbers defined as Integer() = {1, 2, 3, 4, 5}.

To get the first even number in the sequence, apply the last() function as follows:

The output is 4.

The LastOrDefault() function returns the last element, or a default value if no element satisfies the condition.

Assume you have a variable called numbers defined as Integer() = {1, 2, 3, 4, 5}.

To get the first odd number in the sequence, apply the FirstOrDefault() function as follows:

The output is 5.

The Skip() function skips a specified number of elements in a sequence.

Assume you have a variable called numbers defined as Integer() = {1, 2, 3, 4, 5}.

To skip the first two elements in the sequence, apply the Skip() function as follows:

The output is {3, 4, 5}.

The SkipWhile() function skips elements until a condition is no longer satisfied.

Assume you have a variable called numbers defined as Integer() = {1, 2, 3, 4, 5}.

To skip the numbers which are lower than 3, apply the SkipWhile() function as follows:

The output is {3, 4, 5}.

The Take() function returns a specified number of elements from the start of a sequence.

Assume you have a variable called numbers defined as Integer() = {1, 2, 3, 4, 5}.

To get the first three elements in the sequence, apply the Take() function as follows:

The output is {1, 2, 3}.

The TakeWhile() returns elements until a condition is no longer satisfied.

Assume you have a variable called numbers defined as Integer() = {1, 2, 3, 4, 5}.

To get the numbers which are lower than 4, apply the TakeWhile() function as follows:

The output is {1, 2, 3}.

The Any() function returns true if any element in a sequence satisfies a specified condition.

Assume you have a variable called numbers defined as Integer() = {1, 2, 3, 4, 5}.

To find out if at least one number in the sequence is even, apply the Any() function as follows:

The output is true.

The All() returns true if all elements in a sequence satisfy a specified condition.

Assume you have a variable called numbers defined as Integer() = {1, 2, 3, 4, 5}.

To find out if all the numbers in the sequence are positive, apply the All() function as follows:

The output is true.

The list function AddItemToList() adds a new item to an existing list.

To add an item to the generic list, assign it the following value:

The list function DeleteItemFromList() deletes items from an existing list.

To delete an item from the generic list, assign it the following value:

The list function UpdateListItemAtIndex() updates items in an existing list.

To update an item in the generic list, assign it the following value: