Class CollectionExtensions

Namespace

Badeend.Results.Extensions

Assembly

Badeend.Result.dll

Fallible overloads for commonly used collection operations.

public static class CollectionExtensions

Inheritance

object

CollectionExtensions

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Methods

TryElementAt<T>(IEnumerable<T>, int)

Get the element at the specified index in the sequence. Returns an error if the index exceeds the sequence length.

public static Result<T> TryElementAt<T>(this IEnumerable<T> source, int index)

Parameters

source IEnumerable<T>

index int

Returns

Result<T>

Type Parameters

T

Remarks

This method is similar to:

• ElementAt<TSource>(IEnumerable<TSource>, int), except that this method doesn't throw if the index exceeds the sequence length.
• ElementAtOrDefault<TSource>(IEnumerable<TSource>, int), except that this method retains the distinction between: the index was out of bounds, and: the index exists but happens to contains the default value.

Exceptions

ArgumentNullException

source is null.

ArgumentOutOfRangeException

index is negative.

TryFirst<T>(IEnumerable<T>)

Get the first element in the collection. Returns an error if the collection is empty.

public static Result<T> TryFirst<T>(this IEnumerable<T> source)

Parameters

source IEnumerable<T>

Returns

Result<T>

Type Parameters

T

Remarks

This method is similar to:

• First<TSource>(IEnumerable<TSource>), except that this method doesn't throw for empty collections.
• FirstOrDefault<TSource>(IEnumerable<TSource>), except that this method retains the distinction between: an empty collection, and: a non-empty collection whose first element happens to be the default value.

Exceptions

ArgumentNullException

source is null.

TryFirst<T>(IEnumerable<T>, Func<T, bool>)

Get the first element in the collection that satisfies a specified condition. Returns an error if no element in the collection satisfies the condition in predicate.

public static Result<T> TryFirst<T>(this IEnumerable<T> source, Func<T, bool> predicate)

Parameters

source IEnumerable<T>

predicate Func<T, bool>

Returns

Result<T>

Type Parameters

T

Remarks

This method is similar to:

• First<TSource>(IEnumerable<TSource>, Func<TSource, bool>), except that this method doesn't throw if there were no matches.
• FirstOrDefault<TSource>(IEnumerable<TSource>, Func<TSource, bool>), except that this method retains the distinction between: there were no matches, and: there was a match but the element happens to be the default value.

Exceptions

ArgumentNullException

source or predicate is null.

TryGetValue<TKey, TValue>(IReadOnlyDictionary<TKey, TValue>, TKey)

Get the value associated with the specified key. Returns an error if the key was not found.

public static Result<TValue> TryGetValue<TKey, TValue>(this IReadOnlyDictionary<TKey, TValue> dictionary, TKey key)

Parameters

dictionary IReadOnlyDictionary<TKey, TValue>

key TKey

Returns

Result<TValue>

Type Parameters

TKey

TValue

Exceptions

ArgumentNullException

dictionary is null.

TryIndexOf<T>(IReadOnlyList<T>, T)

Find the index of the first occurrence of item in the list. Returns an error if not found.

public static Result<int> TryIndexOf<T>(this IReadOnlyList<T> list, T item)

Parameters

list IReadOnlyList<T>

item T

Returns

Result<int>

Type Parameters

T

Remarks

Similar to IndexOf(T), but with the added guarantee that the returned integer is always a valid index (i.e. not negative).

Exceptions

ArgumentNullException

list is null.

TryLastIndexOf<T>(IReadOnlyList<T>, T)

Find the index of the last occurrence of item in the list. Returns an error if not found.

public static Result<int> TryLastIndexOf<T>(this IReadOnlyList<T> list, T item)

Parameters

list IReadOnlyList<T>

item T

Returns

Result<int>

Type Parameters

T

Remarks

Similar to LastIndexOf(T), but with the added guarantee that the returned integer is always a valid index (i.e. not negative).

Exceptions

ArgumentNullException

list is null.

TryLast<T>(IEnumerable<T>)

Get the last element in the collection. Returns an error if the collection is empty.

public static Result<T> TryLast<T>(this IEnumerable<T> source)

Parameters

source IEnumerable<T>

Returns

Result<T>

Type Parameters

T

Remarks

This method is similar to:

• Last<TSource>(IEnumerable<TSource>), except that this method doesn't throw for empty collections.
• LastOrDefault<TSource>(IEnumerable<TSource>), except that this method retains the distinction between: an empty collection, and: a non-empty collection whose last element happens to be the default value.

Exceptions

ArgumentNullException

source is null.

TryLast<T>(IEnumerable<T>, Func<T, bool>)

Get the last element in the collection that satisfies a specified condition. Returns an error if no element in the collection satisfies the condition in predicate.

public static Result<T> TryLast<T>(this IEnumerable<T> source, Func<T, bool> predicate)

Parameters

source IEnumerable<T>

predicate Func<T, bool>

Returns

Result<T>

Type Parameters

T

Remarks

This method is similar to:

• Last<TSource>(IEnumerable<TSource>, Func<TSource, bool>), except that this method doesn't throw if there were no matches.
• LastOrDefault<TSource>(IEnumerable<TSource>, Func<TSource, bool>), except that this method retains the distinction between: there were no matches, and: there was a match but the element happens to be the default value.

Exceptions

ArgumentNullException

source or predicate is null.

TryMax<T>(IEnumerable<T>)

Get the maximum value in the sequence. Returns an error if the sequence does not contain any non-null elements.

public static Result<T> TryMax<T>(this IEnumerable<T> source)

Parameters

source IEnumerable<T>

Returns

Result<T>

Type Parameters

T

Remarks

Similar to Max<TSource>(IEnumerable<TSource>).

Exceptions

ArgumentNullException

source is null.

TryMin<T>(IEnumerable<T>)

Get the minimum value in the sequence. Returns an error if the sequence does not contain any non-null elements.

public static Result<T> TryMin<T>(this IEnumerable<T> source)

Parameters

source IEnumerable<T>

Returns

Result<T>

Type Parameters

T

Remarks

Similar to Min<TSource>(IEnumerable<TSource>).

Exceptions

ArgumentNullException

source is null.

TryRemove<TKey, TValue>(IDictionary<TKey, TValue>, TKey)

Remove the value with the specified key from the dictionary. Returns the removed value or an error if the key was not found.

public static Result<TValue> TryRemove<TKey, TValue>(this IDictionary<TKey, TValue> dictionary, TKey key)

Parameters

dictionary IDictionary<TKey, TValue>

key TKey

Returns

Result<TValue>

Type Parameters

TKey

TValue

Exceptions

ArgumentNullException

dictionary is null.

TrySingle<T>(IEnumerable<T>)

Get the only element in the collection. Returns an error if there is not exactly one element in the collection.

public static Result<T, TrySingleError> TrySingle<T>(this IEnumerable<T> source)

Parameters

source IEnumerable<T>

Returns

Result<T, TrySingleError>

Type Parameters

T

Remarks

This method is similar to:

• Single<TSource>(IEnumerable<TSource>), except that this method doesn't throw for wrongly-sized collections.
• SingleOrDefault<TSource>(IEnumerable<TSource>), except that this method retains the distinction between: the collection doesn't contain a single element, and: the collection has exactly one element that happens to be the default value.

Exceptions

ArgumentNullException

source is null.

TrySingle<T>(IEnumerable<T>, Func<T, bool>)

Get the only element in the collection that satisfies a specified condition. Returns an error if there is not exactly one element matching the predicate.

public static Result<T, TrySingleError> TrySingle<T>(this IEnumerable<T> source, Func<T, bool> predicate)

Parameters

source IEnumerable<T>

predicate Func<T, bool>

Returns

Result<T, TrySingleError>

Type Parameters

T

Remarks

This method is similar to:

• Single<TSource>(IEnumerable<TSource>, Func<TSource, bool>), except that this method doesn't throw if there wasn't exactly one match.
• SingleOrDefault<TSource>(IEnumerable<TSource>, Func<TSource, bool>), except that this method retains the distinction between: there wasn't exactly one match, and: there was a single match but the element happens to be the default value.

Exceptions

ArgumentNullException

source or predicate is null.