R practice in Computational Biology
Browse the rooms before signing in. All rooms are free with an account. Practice does not issue certificates.
Count the Usable Bases
A field sequencer exported gaps and unknowns. Count only canonical DNA bases before the team compares samples.
sequence-qc. Free with an account.
Find Every Motif
A curator needs every overlapping occurrence of a short motif, including repeats that share residues.
motif-search. Free with an account.
Read the Coding Frame
A gene model needs the number of complete codons in a sequence. Return complete triplets and leave trailing bases unclaimed.
coding-sequence. Free with an account.
Summarize Library Depth
A sequencing run has one count column per sample. Return the named library totals without losing sample identity.
count-matrix. Free with an account.
Balance Assay Blocks
RNA and protein blocks have different feature counts. Center each block and scale it to unit Frobenius norm.
block-scaling. Free with an account.
Measure Sequence Divergence
Two aligned sequences disagree at some usable positions. Report the mismatch fraction without counting gaps.
sequence-distance. Free with an account.
Merge Domain Hits
A domain scan emitted overlapping intervals. Merge them into non-overlapping one-based closed regions.
intervals. Free with an account.
Rank Variable Genes
An assay needs a deterministic shortlist. Rank gene rows by variance and use gene name to settle ties.
feature-ranking. Free with an account.
Audit the Sample Map
A multi-omic cohort map may omit assay samples. Return every missing assay::sample key.
sample-identity. Free with an account.
Bootstrap a Clade
Replicate trees list their supported splits. Calculate target support using successful replicates only.
bootstrap-support. Free with an account.
Keep Subjects Together
Repeated samples must never cross validation folds. Assign deterministic folds by unique subject.
grouped-validation. Free with an account.
Score a Protein Candidate
A review queue needs a transparent evidence score. Reward assays, reciprocal homology, and motifs, then subtract conflicts.
evidence-scoring. Free with an account.
Audit Subgroup Loss
A model performs unevenly across groups. Return the largest difference in mean loss while keeping every group in the audit.
subgroup-audit. Free with an account.
Correct Hidden Substitutions
Observed divergence misses repeated substitutions. Apply the Jukes-Cantor correction and mark saturation unavailable.
evolution-model. Free with an account.
Link Omic Views Cautiously
Two subject-aligned features may move together. Align subject names and return their Pearson correlation.
cross-omic-association. Free with an account.
Fit the Molecular Clock
Sampling dates and root-to-tip distances need an aligned regression. Return the slope without trusting vector order.
clock-regression. Free with an account.
Challenge Protein Claims
A protein candidate has coverage, conflicts, and assay support. Return the narrowest defensible review tier.
bounded-interpretation. Free with an account.
Detect Cohort Leakage
A preprocessing log lists subjects used to fit each transform. Flag any held-out subject appearing in a fit.
leakage-audit. Free with an account.
Publish the Evidence Dossier
A project is ready only if identity, leakage, coverage, and validation checks all pass. Return the highest-priority status.
evidence-dossier. Free with an account.
Reconstruct the First Branch
A distance matrix needs a deterministic first average-linkage merge. Return the lexical pair among tied minima.
tree-reconstruction. Free with an account.