Agent skill
bio-expression-matrix-counts-ingest
Load gene expression count matrices from various formats including CSV, TSV, featureCounts, Salmon, kallisto, and 10X. Use when importing quantification results for downstream analysis.
Install this agent skill to your Project
npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/data/counts-ingest
SKILL.md
Count Matrix Ingestion
Basic CSV/TSV Loading
import pandas as pd
# TSV with gene IDs as first column
counts = pd.read_csv('counts.tsv', sep='\t', index_col=0)
# CSV with header
counts = pd.read_csv('counts.csv', index_col=0)
# Skip comment lines
counts = pd.read_csv('counts.txt', sep='\t', index_col=0, comment='#')
featureCounts Output
import pandas as pd
# featureCounts format has 6 metadata columns before counts
fc = pd.read_csv('featurecounts.txt', sep='\t', comment='#')
counts = fc.set_index('Geneid').iloc[:, 5:] # Skip Chr, Start, End, Strand, Length
counts.columns = [c.replace('.bam', '').split('/')[-1] for c in counts.columns]
Salmon Quant Files
import pandas as pd
from pathlib import Path
def load_salmon_quants(quant_dirs, column='NumReads'):
'''Load multiple Salmon quant.sf files into a count matrix.'''
dfs = {}
for qdir in quant_dirs:
sample = Path(qdir).name
sf = pd.read_csv(f'{qdir}/quant.sf', sep='\t', index_col=0)
dfs[sample] = sf[column]
return pd.DataFrame(dfs)
# Usage
quant_dirs = ['salmon_out/sample1', 'salmon_out/sample2', 'salmon_out/sample3']
counts = load_salmon_quants(quant_dirs, column='NumReads')
tpm = load_salmon_quants(quant_dirs, column='TPM')
kallisto Abundance Files
import pandas as pd
from pathlib import Path
def load_kallisto_quants(abundance_files, column='est_counts'):
'''Load multiple kallisto abundance.tsv files.'''
dfs = {}
for f in abundance_files:
sample = Path(f).parent.name
ab = pd.read_csv(f, sep='\t', index_col=0)
dfs[sample] = ab[column]
return pd.DataFrame(dfs)
# Usage
files = ['kallisto_out/sample1/abundance.tsv', 'kallisto_out/sample2/abundance.tsv']
counts = load_kallisto_quants(files, column='est_counts')
tpm = load_kallisto_quants(files, column='tpm')
10X Genomics Sparse Matrix
import scanpy as sc
# Load 10X directory (contains matrix.mtx, genes.tsv/features.tsv, barcodes.tsv)
adata = sc.read_10x_mtx('filtered_feature_bc_matrix/')
# Load 10X H5 file
adata = sc.read_10x_h5('filtered_feature_bc_matrix.h5')
# Convert to dense DataFrame if needed
counts = adata.to_df()
AnnData H5AD Files
import anndata as ad
import scanpy as sc
# Load h5ad
adata = sc.read_h5ad('data.h5ad')
# Access count matrix
counts = adata.to_df() # Dense DataFrame
sparse_counts = adata.X # Sparse matrix (if stored sparse)
# Access raw counts if normalized data is in .X
raw_counts = adata.raw.to_adata().to_df()
RDS Files (from R)
import pyreadr
# Read RDS file
result = pyreadr.read_r('counts.rds')
counts = result[None] # Access the data
# For Seurat objects, use anndata2ri or convert in R first
Combine Multiple Files
import pandas as pd
from pathlib import Path
def combine_count_files(file_pattern, index_col=0, sep='\t'):
'''Combine multiple count files into one matrix.'''
files = sorted(Path('.').glob(file_pattern))
dfs = {}
for f in files:
sample = f.stem.replace('_counts', '')
dfs[sample] = pd.read_csv(f, sep=sep, index_col=index_col).iloc[:, 0]
return pd.DataFrame(dfs)
# Usage
counts = combine_count_files('counts/*_counts.tsv')
Filter Low-Count Genes
# Keep genes with at least 10 counts in at least 3 samples
min_counts, min_samples = 10, 3
expressed = (counts >= min_counts).sum(axis=1) >= min_samples
counts_filtered = counts.loc[expressed]
# Alternative: total counts threshold
counts_filtered = counts[counts.sum(axis=1) >= 50]
Handle Gene ID Versions
# Remove Ensembl version numbers (ENSG00000123456.12 -> ENSG00000123456)
counts.index = counts.index.str.split('.').str[0]
# Or keep as-is for compatibility
Save Count Matrix
# Save as TSV
counts.to_csv('count_matrix.tsv', sep='\t')
# Save as compressed
counts.to_csv('count_matrix.tsv.gz', sep='\t', compression='gzip')
# Save as AnnData
import anndata as ad
adata = ad.AnnData(counts)
adata.write_h5ad('counts.h5ad')
R Loading Equivalents
# Basic CSV/TSV
counts <- read.csv('counts.csv', row.names=1)
counts <- read.delim('counts.tsv', row.names=1)
# featureCounts
fc <- read.delim('featurecounts.txt', comment.char='#', row.names=1)
counts <- fc[, 6:ncol(fc)]
# tximport for Salmon/kallisto
library(tximport)
files <- file.path('salmon_out', samples, 'quant.sf')
txi <- tximport(files, type='salmon', txOut=TRUE)
counts <- txi$counts
Related Skills
- rna-quantification/featurecounts-counting - Generate featureCounts output
- rna-quantification/alignment-free-quant - Generate Salmon/kallisto output
- expression-matrix/sparse-handling - Memory-efficient storage
- expression-matrix/gene-id-mapping - Convert gene identifiers
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