Newick Tree — Branch Lengths and Support Values (.nwk)
A six-taxon Newick tree with branch lengths on every edge and bootstrap-style support values written as internal node labels. That support notation is ambiguous by design in Newick — the same position can hold a node name — which is precisely what a parser has to decide about.
(((TAXON_A:0.11250,TAXON_B:0.09880)95:0.04310,(TAXON_C:0.13400,TAXON_D:0.12070)87:0.03720)100:0.02150,TAXON_E:0.21860,TAXON_F:0.19940);
Specifications
- Leaves
- 6
- Internal Nodes
- 3
- Has Branch Lengths
- true
- Has Support Values
- true
- Rooted
- false
- Terminator
- ;
- Support Notation
- an unquoted integer label on the internal node
Testing contract
Expected to pass- Scenario
- Parse the tree and report the leaf names, each branch length and the label on every internal node.
- Expected result
- Six leaves parse with branch lengths to five decimals, three internal nodes carry the labels 95, 87 and 100, and the string terminates on a semicolon.
What is a .nwk file?
Newick is a compact parenthetical notation for trees, used across phylogenetics. Nested parentheses describe the topology, commas separate siblings, names label leaves and optionally internal nodes, a colon introduces a branch length, and a semicolon terminates the tree. Internal-node labels are frequently repurposed to carry bootstrap support values, which is why a parser must not assume a label is a taxon name.
How to use this file
Use an example .nwk file to test tree parsers and phylogeny viewers, checking quoted labels containing punctuation, missing branch lengths, unrooted versus rooted forms, and that deeply nested trees do not overflow a recursive reader.
How to use this file for testing
“Newick Tree — Branch Lengths and Support Values (.nwk)” is a deterministic Novus Examples fixture for Scientific data, Editor testing. Citation catalogs (BibTeX, RIS), chemistry structures (MDL Molfile, PDB), and gridded binary data (NetCDF, FITS) — for testing reference managers, molecule viewers, and scientific-data loaders.
Documented properties for this file: NWK · 136 bytes. Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.
Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such — expect parsers to fail loudly rather than silently accept them.
Scientific fixtures are small, valid, and fully synthetic — no real organism, patient, sample, or observation. Point your parser or loader at the file and check it reads the documented records, variables, or headers; binary formats ship a readable twin or metadata listing for comparison.
Related files
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- fastaFASTA Contigs — One Line Per Record (.fasta)The same four contigs written one sequence per line rather than wrapped, which is how many pipelines emit FASTA and how many line-oriented parsers assume it always looks. Comparing against the wrapped twin proves a parser joins continuation lines instead of taking the first one.
- fastaFASTA Contigs — Wrapped at 60 Columns (.fasta)Four 600-base synthetic contigs wrapped at the conventional 60 columns, with the length and an invented organism name in each header. The sequences come from a fixed seed, so they are reproducible and belong to nothing that exists.
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