Skip to content

fix: allow undirected fixed length pattern #781

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
SemyonSinchenko merged 1 commit into from
Jan 27, 2026
Merged

fix: allow undirected fixed length pattern #781

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
63 changes: 40 additions & 23 deletions core/src/main/scala/org/graphframes/GraphFrame.scala
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -470,6 +470,7 @@ class GraphFrame private (
*/
def find(pattern: String): DataFrame = {
val VarLengthPattern = """\((\w+)\)-\[(\w*)\*(\d*)\.\.(\d*)\]-(>?)\((\w+)\)""".r
val FixedLengthUndirectedPattern = """\((\w+)\)-\[(\w*)\*(\d*)\]-\((\w+)\)""".r
Comment thread
SemyonSinchenko marked this conversation as resolved.

pattern match {
case VarLengthPattern(src, name, min, max, direction, dst) =>
Expand All @@ -478,37 +479,53 @@ class GraphFrame private (
s"Unbounded length patten ${pattern} is not supported! " +
"Please a pattern of defined length.")
}
val strToSeq: Seq[(Int, String)] = (min.toInt to max.toInt).reverse.map { hop =>
(hop, s"($src)-[$name*$hop]->($dst)")
}
val strToSeqReverse: Seq[(Int, String)] = if (direction.isEmpty) {
(min.toInt to max.toInt).reverse.map(hop => (hop, s"($src)<-[$name*$hop]-($dst)"))
} else {
Seq.empty[(Int, String)]
}

val out: Seq[DataFrame] = strToSeq.map { case (hop, patternStr) =>
findAugmentedPatterns(patternStr)
.withColumn("_hop", lit(hop))
.withColumn("_pattern", lit(patternStr))
.withColumn("_direction", lit("out"))
}
findVarLengthPattern(src, name, min.toInt, max.toInt, direction, dst)

val in: Seq[DataFrame] = strToSeqReverse.map { case (hop, patternStr) =>
findAugmentedPatterns(patternStr)
.withColumn("_hop", lit(hop))
.withColumn("_pattern", lit(patternStr))
.withColumn("_direction", lit("in"))
case FixedLengthUndirectedPattern(src, name, hop, dst) =>
if (hop.isEmpty) {
throw new InvalidParseException("Missing hop!")
}

val ret = (out ++ in).reduce((a, b) => a.unionByName(b, allowMissingColumns = true))
ret.orderBy("_hop", "_direction")
findVarLengthPattern(src, name, hop.toInt, hop.toInt, "", dst)

case _ =>
findAugmentedPatterns(pattern)
}
}

def findVarLengthPattern(
src: String,
name: String,
min: Int,
max: Int,
direction: String,
dst: String): DataFrame = {
val strToSeq: Seq[(Int, String)] = (min to max).reverse.map { hop =>
(hop, s"($src)-[$name*$hop]->($dst)")
}
val strToSeqReverse: Seq[(Int, String)] = if (direction.isEmpty) {
(min to max).reverse.map(hop => (hop, s"($src)<-[$name*$hop]-($dst)"))
} else {
Seq.empty[(Int, String)]
}

val out: Seq[DataFrame] = strToSeq.map { case (hop, patternStr) =>
findAugmentedPatterns(patternStr)
.withColumn("_hop", lit(hop))
.withColumn("_pattern", lit(patternStr))
.withColumn("_direction", lit("out"))
}

val in: Seq[DataFrame] = strToSeqReverse.map { case (hop, patternStr) =>
findAugmentedPatterns(patternStr)
.withColumn("_hop", lit(hop))
.withColumn("_pattern", lit(patternStr))
.withColumn("_direction", lit("in"))
}

val ret = (out ++ in).reduce((a, b) => a.unionByName(b, allowMissingColumns = true))
ret.orderBy("_hop", "_direction")
}

def findAugmentedPatterns(pattern: String): DataFrame = {
val patterns = Pattern.parse(pattern)

Expand Down
8 changes: 8 additions & 0 deletions core/src/test/scala/org/graphframes/PatternMatchSuite.scala
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -790,6 +790,14 @@ class PatternMatchSuite extends SparkFunSuite with GraphFrameTestSparkContext {
assert(res.except(expected).isEmpty && expected.except(res).isEmpty)
}

test("undirected fixed-length pattern") {
val res = g.find("(u)-[e*3]-(v)")
val expected = g.find("(u)-[e*3..3]-(v)")

assert(res.schema === expected.schema)
assert(res.except(expected).isEmpty && expected.except(res).isEmpty)
}

test("stateful predicates via UDFs") {
val chain4 = g
.find("(a)-[ab]->(b); (b)-[bc]->(c); (c)-[cd]->(d)")
Expand Down