# Useful VB functions

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

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

We grouped several of these functions in a [public app](https://alpha.uipath.com/appdevtest/apps_/default/run/production/2b514bff-2c40-4e9d-a87b-5fa64e21729a/d5edbd5b-1a41-4aca-8df3-652190d0d4ae/ID20cd26edc66248dabc82c528b541e38e/public?el=vb), so you can try out them out and see how they behave.

## VB function: Where

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:

```
words.Where(Function(w) w.Contains("a")).ToList()
```

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

## VB function: Select

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:

```
numbers.Select(Function(n) n * n).ToArray()
```

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

## VB function: Aggregate

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:

```
Dim sum = numbers.Aggregate(Function(acc, n) acc + n)
```

The output is `15`.

## VB function: Group By

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:

```
words.GroupBy(Function(w) w(0))
```

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

## VB function: Order By

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:

```
words.OrderBy(Function(w) w.Length).ToArray()
```

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

## VB function: Join

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

Assume you have two variables:

* `names` defined as `String() = {"John", "Jane", "Joe"}`
* `ages` defined as `Integer() = {25, 30, 35}`

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

```
names.Join(ages, Function(name) name(0), Function(age) age Mod 10, Function(name, age) $"{name}: {age}")
```

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

## VB function: First

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:

```
numbers.First(Function(n) n Mod 2 = 0)
```

The output is `2`.

## VB function: First Or Default

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:

```
numbers.FirstOrDefault(Function(n) n Mod 2 = 1)
```

The output is `1`.

## VB function: Last

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:

```
numbers.Last(Function(n) n Mod 2 = 0)
```

The output is `4`.

## VB function: Last Or Default

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:

```
numbers.LastOrDefault(Function(n) n Mod 2 = 1)
```

The output is `5`.

## VB function: Skip

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:

```
numbers.Skip(2).ToArray()
```

The output is `{3, 4, 5}`.

## VB function: Skip While

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:

```
numbers.SkipWhile(Function(n) n < 3).ToArray()
```

The output is `{3, 4, 5}`.

## VB function: Take

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:

```
numbers.Take(3).ToArray()
```

The output is `{1, 2, 3}`.

## VB function: Take While

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:

```
numbers.TakeWhile(Function(n) n < 4).ToArray()
```

The output is `{1, 2, 3}`.

## VB function: Any

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:

```
numbers.Any(Function(n) n Mod 2 = 0)
```

The output is `true`.

## VB function: All

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:

```
numbers.All(Function(n) n > 0)
```

The output is `true`.

## VB function: Add item to list

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:

```
AddItemToList(Processes.ALLDATATYPES.out_genericList, MainPage.EditGrid.NewItem)
```

## VB function: Delete item from list

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

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

```
DeleteItemFromList(Processes.ALLDATATYPES.out_genericList, MainPage.EditGrid.RowIndex)
```

## VB function: Update list item at index

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

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

```
UpdateListItemAtIndex(Processes.ALLDATATYPES.out_genericList, MainPage.EditGrid.RowIndex, MainPage.EditGrid.SelectedItem)
```