Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression

/
/
gms

Test String

Code Generator

Generated Code

$re = '/(?P<file_number>\d+)\.\s+(?P<filepath>.*?)\n(?P<file_contents>```(.*?)```)(?=\d+\.\s+|$)/ms'; $str = '1. nextflow.config ``` params { inputDir = "data/raw" outputDir = "results" } process { executor = "local" memory = "8 GB" cpus = 4 } ``` 2. main.nf ``` #!/usr/bin/env nextflow params.inputDir = "./data/raw" params.outputDir = "./results" include { preprocess, qualityControl, differentialExpression } from "./scripts" workflow { input: path(inputDir) from params.inputDir output: path(outputDir) into results preprocess_output, quality_control_output, differential_expression_output = script { preprocess(inputDir) } quality_control_output = script { qualityControl(preprocess_output) } differential_expression_output = script { differentialExpression(preprocess_output) } } ``` 3. scripts/preprocess.sh ``` #!/bin/bash inputDir=$1 # Trim reads using Trimmomatic trimmomatic PE ${inputDir}/sample_R1.fastq.gz ${inputDir}/sample_R2.fastq.gz ${inputDir}/sample_R1.trimmed.fastq.gz ${inputDir}/sample_R1.unpaired.fastq.gz ${inputDir}/sample_R2.trimmed.fastq.gz ${inputDir}/sample_R2.unpaired.fastq.gz ILLUMINACLIP:adapters.fa:2:30:10 LEADING:3 TRAILING:3 SLIDINGWINDOW:4:15 MINLEN:36 # Align trimmed reads using HISAT2 hisat2 -x genome_index -1 ${inputDir}/sample_R1.trimmed.fastq.gz -2 ${inputDir}/sample_R2.trimmed.fastq.gz -S ${inputDir}/sample.sam # Convert SAM to BAM samtools view -bS ${inputDir}/sample.sam > ${inputDir}/sample.bam # Sort BAM file samtools sort ${inputDir}/sample.bam -o ${inputDir}/sample.sorted.bam # Index sorted BAM file samtools index ${inputDir}/sample.sorted.bam # Remove intermediate files rm ${inputDir}/sample.sam ${inputDir}/sample.bam ``` 4. scripts/quality_control.sh ``` #!/bin/bash inputDir=$1 # Run FastQC on trimmed reads fastqc ${inputDir}/sample_R1.trimmed.fastq.gz ${inputDir}/sample_R2.trimmed.fastq.gz -o ${inputDir} # Move FastQC output to results directory mv ${inputDir}/*.html ${inputDir}/*.zip ${inputDir}/../results/logs ``` 5. scripts/differential_expression.sh ``` #!/bin/bash inputDir=$1 # Count reads using featureCounts featureCounts -T 4 -a annotation.gtf -o ${inputDir}/counts.txt ${inputDir}/sample.sorted.bam # Perform differential expression analysis using DESeq2 Rscript differential_expression.R ${inputDir}/counts.txt ${inputDir}/../results/differential_expression_results.txt ``` Note: The contents of the `data/` and `results/` directories are not provided as they would depend on the specific input data and expected output structure. '; preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0); // Print the entire match result var_dump($matches);

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php