UKismetStringLibrary::DiffString

function Engine Blueprint Since unknown

#include "Kismet/KismetStringLibrary.h"

Access: public Specifiers: staticBlueprintCallable

Description

Returns a human-readable description of the line-based LCS (longest common subsequence) difference between two strings, marking modifications, removals, and additions with ~, -, and + symbols.

Caveats & Gotchas

• Only compiled under WITH_EDITOR — this function does not exist in packaged/shipping builds, so calling code guarded incorrectly will fail to compile or link there.
• The header explicitly warns the diff is expensive for large strings; it's intended for editor tooling, not runtime gameplay logic.
• The output is a formatted, human-readable report, not structured data — it isn't meant to be parsed programmatically.

Signature

static FString DiffString(const FString& First, const FString& Second)

Parameters

Name	Type	Description	Default
First	const FString&	The string to treat as the basis for the comparison.	—
Second	const FString&	The string to treat as the change against First.	—

Return Type

FString

Example

Diff two config strings in an editor tool C++

#if WITH_EDITOR
const FString Report = UKismetStringLibrary::DiffString(OldConfig, NewConfig);
UE_LOG(LogTemp, Log, TEXT("%s"), *Report);
#endif

Version History

Introduced in: unknown

Version	Status	Notes
5.6	stable	—

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