---
title: Collection Implementations
framework: swift
role: collectionGroup
role_heading: API Collection
path: swift/collectionofone/collection-implementations
---

# Collection Implementations

## Topics

### Structures

- [CollectionOfOne.Iterator](swift/collectionofone/iterator.md)

### Instance Properties

- [count](swift/collectionofone/count.md)
- [first](swift/collectionofone/first.md)
- [isEmpty](swift/collectionofone/isempty.md)
- [underestimatedCount](swift/collectionofone/underestimatedcount.md)

### Instance Methods

- [drop(while:)](swift/collectionofone/drop(while:).md)
- [dropFirst(_:)](swift/collectionofone/dropfirst(_:).md)
- [firstIndex(of:)](swift/collectionofone/firstindex(of:).md)
- [firstIndex(where:)](swift/collectionofone/firstindex(where:).md)
- [formIndex(_:offsetBy:)](swift/collectionofone/formindex(_:offsetby:).md)
- [formIndex(_:offsetBy:limitedBy:)](swift/collectionofone/formindex(_:offsetby:limitedby:).md)
- [formIndex(after:)](swift/collectionofone/formindex(after:).md)
- [index(of:)](swift/collectionofone/index(of:).md)
- [indices(of:)](swift/collectionofone/indices(of:).md)
- [indices(where:)](swift/collectionofone/indices(where:).md)
- [makeIterator()](swift/collectionofone/makeiterator().md)
- [map(_:)](swift/collectionofone/map(_:)-6e1xi.md)
- [prefix(_:)](swift/collectionofone/prefix(_:).md)
- [prefix(through:)](swift/collectionofone/prefix(through:).md)
- [prefix(upTo:)](swift/collectionofone/prefix(upto:).md)
- [prefix(while:)](swift/collectionofone/prefix(while:).md)
- [randomElement()](swift/collectionofone/randomelement().md)
- [randomElement(using:)](swift/collectionofone/randomelement(using:).md)
- [removingSubranges(_:)](swift/collectionofone/removingsubranges(_:).md)
- [split(maxSplits:omittingEmptySubsequences:whereSeparator:)](swift/collectionofone/split(maxsplits:omittingemptysubsequences:whereseparator:).md)
- [split(separator:maxSplits:omittingEmptySubsequences:)](swift/collectionofone/split(separator:maxsplits:omittingemptysubsequences:)-1a0oe.md)
- [suffix(from:)](swift/collectionofone/suffix(from:).md)

### Subscripts

- [subscript(_:)](swift/collectionofone/subscript(_:)-3dvjk.md)
- [subscript(_:)](swift/collectionofone/subscript(_:)-59bql.md)
- [subscript(_:)](swift/collectionofone/subscript(_:)-5iy5s.md)
- [subscript(_:)](swift/collectionofone/subscript(_:)-y23p.md)

### Type Aliases

- [CollectionOfOne.Index](swift/collectionofone/index.md)
- [CollectionOfOne.Indices](swift/collectionofone/indices.md)
- [CollectionOfOne.SubSequence](swift/collectionofone/subsequence.md)