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  3. FString

FString

A dynamically sizeable string.

API > API/Runtime > API/Runtime/Core > API/Runtime/Core/Containers

Inheritance Hierarchy

References

   
Module Core
Header /Engine/Source/Runtime/Core/Public/Containers/UnrealString.h
Include #include "Containers/UnrealString.h"

Syntax

class FString

Remarks

A dynamically sizeable string. When dealing with UTF-8 literals, the following advice is recommended:

  • Do not use the u8"..." prefix (gives the wrong array type until C++20).
  • Use UTF8TEXT("...") for array literals (type is const UTF8CHAR[n]).
  • Use UTF8TEXTVIEW("...") for string view literals (type is FUtf8StringView).
  • Use or escape sequences rather than to specify Unicode code points.

Constructors

  Type Name Description
Public function  

FString ()

  
Public function  

FString ( FString&& Other,
int32 ExtraSlack
)

 Create a copy of the Other string with extra space for characters at the end of the string
Public function  

FString ( int32 Len,
const ANSICHAR* Str
)

 Construct from null-terminated C substring or nullptr
Public function  

FString ( int32 Len,
const WIDECHAR* Str
)

  
Public function  

FString ( int32 Len,
const UTF8CHAR* Str
)

  
Public function  

FString ( int32 Len,
const UCS2CHAR* Str
)

  
Public function  

FString ( const ANSICHAR* Str,
int32 ExtraSlack
)

 Construct from null-terminated C string or nullptr with extra slack on top of original string length
Public function  

FString ( const WIDECHAR* Str,
int32 ExtraSlack
)

  
Public function  

FString ( const UTF8CHAR* Str,
int32 ExtraSlack
)

  
Public function  

FString ( const UCS2CHAR* Str,
int32 ExtraSlack
)

  
Public function  

FString ( CharRangeType&& Str,
int32 ExtraSlack
)

 Construct from contiguous range of characters with extra slack on top of original string length
Public function    
Public function  

FString ( const FString&
)

  
Public function  

FString ( const ANSICHAR* Str
)

 Construct from null-terminated C string or nullptr
Public function  

FString ( const WIDECHAR* Str
)

  
Public function  

FString ( const UTF8CHAR* Str
)

  
Public function  

FString ( const UCS2CHAR* Str
)

  
Public function  

FString ( CharRangeType&& Str
)

 Construct from contiguous range of characters such as FStringView or FStringBuilderBase
Public function  

FString ( const FString& Other,
int32 ExtraSlack
)

 Create a copy of the Other string with extra space for characters at the end of the string

Functions

  Type Name Description
Public function FString &

Append ( const CharType* Str,
int32 Count
)

 Append a string and return a reference to this
Public function FString &

Append ( CharRangeType&& Str
)

 Append a string and return a reference to this
Public function FString &

Append ( CharType* Str
)

 Append a valid null-terminated string and return a reference to this
Public function FString &

AppendChar ( TCHAR InChar
)

 Append a single character and return a reference to this
Public function void

AppendChars ( const WIDECHAR* Str,
int32 Count
)

 Appends a character range without null-terminators in it
Public function void

AppendChars ( const ANSICHAR* Str,
int32 Count
)

 Appends a character range without null-terminators in it
Public function void

AppendChars ( const UCS2CHAR* Str,
int32 Count
)

 Appends a character range without null-terminators in it
Public function void

AppendChars ( const UTF8CHAR* Str,
int32 Count
)

 Appends a character range without null-terminators in it
Public function FString &

Appendf ( const FmtType& Fmt,
Types... Args
)

 Just like Printf, but appends the formatted text to the existing FString instead.
Public function void

AppendInt ( int32 InNum
)

 Appends the integer InNum to this string
Public function DataType::RangedForIteratorType

begin ()

 DO NOT USE DIRECTLY STL-like iterators to enable range-based for loop support.
Public function Const DataType::RangedForConstIteratorType

begin ()

  
Public function Const void Run slow checks on this string
Public function Static FString

Chr ( TCHAR Ch
)

 Returns a string containing only the Ch character
Public function Static FString

ChrN ( int32 NumCharacters,
TCHAR Char
)

 Returns a string that is full of a variable number of characters
Public function Const int32

Compare ( const FString& Other,
ESearchCase::Type SearchCase
)

 Lexicographically tests how this string compares to the Other given string
Public function Const bool

Contains ( const TCHAR* SubStr,
int32 SubStrLen,
ESearchCase::Type SearchCase,
ESearchDir::Type SearchDir
)

 Returns whether this string contains the specified substring.
Public function Const bool

Contains ( const FString& SubStr,
ESearchCase::Type SearchCase,
ESearchDir::Type SearchDir
)

 Returns whether this string contains the specified substring.
Public function Const bool

Contains ( const TCHAR* SubStr,
ESearchCase::Type SearchCase,
ESearchDir::Type SearchDir
)

 Returns whether this string contains the specified substring.
Public function Const bool

Contains ( TCharRangeType&& SubStr,
ESearchCase::Type SearchCase,
ESearchDir::Type SearchDir
)

 Returns whether this string contains the specified substring.
Public function FString

ConvertTabsToSpaces ( const int32 InSpacesPerTab
)

 Replaces all instances of '' with TabWidth number of spaces
Public function Const FString

ConvertTabsToSpaces ( const int32 InSpacesPerTab
)

 Replaces all instances of '' with TabWidth number of spaces
Public function void

ConvertTabsToSpacesInline ( const int32 InSpacesPerTab
)

 Replaces all instances of '' with TabWidth number of spaces
Public function Const void  
Public function Const TConstIterator Creates a const iterator for the characters in this string
Public function TIterator Creates an iterator for the characters in this string
Public function Static int32

CullArray ( TArray< FString >* InArray
)

 Takes an array of strings and removes any zero length entries.
Public function void

Empty ()

 Create empty string of given size with zero terminating character
Public function void

Empty ( int32 Slack
)

 Create empty string of given size with zero terminating character
Public function DataType::RangedForIteratorType

end ()

  
Public function Const DataType::RangedForConstIteratorType

end ()

  
Public function Const bool

EndsWith ( TCharRangeType&& InSuffix,
ESearchCase::Type SearchCase
)

 Test whether this string ends with given suffix.
Public function Const bool

EndsWith ( const TCHAR* InSuffix,
ESearchCase::Type SearchCase
)

 Test whether this string ends with given suffix.
Public function Const bool

EndsWith ( const FString& InSuffix,
ESearchCase::Type SearchCase
)

 Test whether this string ends with given suffix.
Public function Const bool

EndsWith ( const TCHAR* InSuffix,
int32 InSuffixLen,
ESearchCase::Type SearchCase
)

 Test whether this string ends with given suffix.
Public function Const bool

Equals ( const FString& Other,
ESearchCase::Type SearchCase
)

 Lexicographically tests whether this string is equivalent to the Other given string
Public function Const int32

Find ( const TCHAR* SubStr,
int32 InSubStrLen,
ESearchCase::Type SearchCase,
ESearchDir::Type SearchDir,
int32 StartPosition
)

 Searches the string for a substring, and returns index into this string of the first found instance.
Public function Const int32

Find ( TCharRangeType&& SubStr,
ESearchCase::Type SearchCase,
ESearchDir::Type SearchDir,
int32 StartPosition
)

 Searches the string for a substring, and returns index into this string of the first found instance.
Public function Const int32

Find ( const TCHAR* SubStr,
ESearchCase::Type SearchCase,
ESearchDir::Type SearchDir,
int32 StartPosition
)

 Searches the string for a substring, and returns index into this string of the first found instance.
Public function Const int32

Find ( const FString& SubStr,
ESearchCase::Type SearchCase,
ESearchDir::Type SearchDir,
int32 StartPosition
)

 Searches the string for a substring, and returns index into this string of the first found instance.
Public function Const bool

FindChar ( TCHAR InChar,
int32& Index
)

 Searches the string for a character
Public function Const bool

FindLastChar ( TCHAR InChar,
int32& Index
)

 Searches the string for the last occurrence of a character
Public function Const int32

FindLastCharByPredicate ( Predicate Pred,
int32 Count
)

 Searches an initial substring for the last occurrence of a character which matches the specified predicate.
Public function Const int32

FindLastCharByPredicate ( Predicate Pred
)

 Searches the string for the last occurrence of a character which matches the specified predicate.
Public function Static FString

Format ( const TCHAR* InFormatString,
const FStringFormatOrderedArguments& InOrderedArguments
)

 Format the specified string using the specified arguments.
Public function Static FString

Format ( const TCHAR* InFormatString,
const FStringFormatNamedArguments& InNamedArguments
)

 Format the specified string using the specified arguments.
Public function Static FString

FormatAsNumber ( int32 InNumber
)

 Takes the number passed in and formats the string in comma format ( 12345 becomes "12,345")
Public function Static FString

FromBlob ( const uint8* SrcBuffer,
const uint32 SrcSize
)

 Converts a buffer to a string
Public function Static FString

FromHexBlob ( const uint8* SrcBuffer,
const uint32 SrcSize
)

 Converts a buffer to a string by hex-ifying the elements
Public function Static FString

FromInt ( int32 Num
)

 Converts an integer to a string.
Public function Const SIZE_T  
Public function DataType & Get string as array of TCHARS
Public function Const const DataType & Get string as const array of TCHARS
Public function void

InsertAt ( int32 Index,
TCHAR Character
)

  
Public function void

InsertAt ( int32 Index,
const FString& Characters
)

  
Public function Const bool

IsEmpty ()

 Test whether this string is empty
Public function Const bool Returns true if the string only contains numeric characters
Public function Const bool

IsValidIndex ( int32 Index
)

 Tests if index is valid, i.e. greater than or equal to zero, and less than the number of characters in this string (excluding the null terminator).
Public function Static FString

Join ( const RangeType& Range,
const TCHAR* Separator
)

 Joins a range of 'something that can be concatentated to strings with +=' together into a single string with separators.
Public function Static FString

JoinBy ( const RangeType& Range,
const TCHAR* Separator,
ProjectionType Proj
)

 Joins a range of elements together into a single string with separators using a projection function.
Public function FString

Left ( int32 Count
)

  
Public function Const FString

Left ( int32 Count
)

 Returns the left most given number of characters
Public function FString

LeftChop ( int32 Count
)

  
Public function Const FString

LeftChop ( int32 Count
)

 Returns the left most characters from the string chopping the given number of characters from the end
Public function void

LeftChopInline ( int32 Count,
bool bAllowShrinking
)

 Modifies the string such that it is now the left most characters chopping the given number of characters from the end
Public function void

LeftInline ( int32 Count,
bool bAllowShrinking
)

 Modifies the string such that it is now the left most given number of characters
Public function Const FString

LeftPad ( int32 ChCount
)

 Pad the left of this string for ChCount characters
Public function Const int32

Len ()

 Get the length of the string, excluding terminating character
Public function Const bool

MatchesWildcard ( const FString& Wildcard,
ESearchCase::Type SearchCase
)

 Searches this string for a given wild cardThis is a simple, SLOW routine. Use with caution
Public function Const bool

MatchesWildcard ( const TCHAR* Wildcard,
int32 WildcardLen,
ESearchCase::Type SearchCase
)

 Searches this string for a given wild cardThis is a simple, SLOW routine. Use with caution
Public function Const bool

MatchesWildcard ( TCharRangeType&& Wildcard,
ESearchCase::Type SearchCase
)

 Searches this string for a given wild cardThis is a simple, SLOW routine. Use with caution
Public function Const bool

MatchesWildcard ( const TCHAR* Wildcard,
ESearchCase::Type SearchCase
)

 Searches this string for a given wild cardThis is a simple, SLOW routine. Use with caution
Public function FString

Mid ( int32 Start,
int32 Count
)

  
Public function Const FString

Mid ( int32 Start
)

 Returns the substring from Start position to the end
Public function FString

Mid ( int32 Start
)

  
Public function Const FString

Mid ( int32 Start,
int32 Count
)

 Returns the substring from Start position for Count characters.
Public function void

MidInline ( int32 Start,
int32 Count,
bool bAllowShrinking
)

 Modifies the string such that it is now the substring from Start position for Count characters.
Public function Const int32

ParseIntoArray ( TArray< FString >& OutArray,
const TCHAR*const* DelimArray,
int32 NumDelims,
bool InCullEmpty
)

 Breaks up a delimited string into elements of a string array, using the given delimiters
Public function Const int32

ParseIntoArray ( TArray< FString >& OutArray,
const TCHAR* pchDelim,
bool InCullEmpty
)

 Breaks up a delimited string into elements of a string array.
Public function Const int32

ParseIntoArrayLines ( TArray< FString >& OutArray,
bool InCullEmpty
)

 Breaks up a delimited string into elements of a string array, using line ending characters
Public function Const int32

ParseIntoArrayWS ( TArray< FString >& OutArray,
const TCHAR* pchExtraDelim,
bool InCullEmpty
)

 Breaks up a delimited string into elements of a string array, using any whitespace and an optional extra delimter, like a ","
Public function void

PathAppend ( const TCHAR* Str,
int32 StrLength
)

 Concatenate this path with given path ensuring the / character is used between them
Public function Static FString

Printf ( const FmtType& Fmt,
Types... Args
)

 Constructs FString object similarly to how classic sprintf works.
Public function Const DataType::RangedForConstReverseIteratorType

rbegin ()

  
Public function DataType::RangedForReverseIteratorType

rbegin ()

  
Public function void

RemoveAt ( int32 Index,
int32 Count,
bool bAllowShrinking
)

 Removes characters within the string.
Public function bool

RemoveFromEnd ( const TCHAR* InSuffix,
int32 InSuffixLen,
ESearchCase::Type SearchCase
)

 Removes the text from the end of the string if it exists.
Public function bool

RemoveFromEnd ( const FString& InSuffix,
ESearchCase::Type SearchCase
)

 Removes the text from the end of the string if it exists.
Public function bool

RemoveFromEnd ( const TCHAR* InSuffix,
ESearchCase::Type SearchCase
)

 Removes the text from the end of the string if it exists.
Public function bool

RemoveFromEnd ( TCharRangeType&& InSuffix,
ESearchCase::Type SearchCase
)

 Removes the text from the end of the string if it exists.
Public function bool

RemoveFromStart ( TCharRangeType&& InPrefix,
ESearchCase::Type SearchCase
)

 Removes the text from the start of the string if it exists.
Public function bool

RemoveFromStart ( const TCHAR* InPrefix,
ESearchCase::Type SearchCase
)

 Removes the text from the start of the string if it exists.
Public function bool

RemoveFromStart ( const FString& InPrefix,
ESearchCase::Type SearchCase
)

 Removes the text from the start of the string if it exists.
Public function bool

RemoveFromStart ( const TCHAR* InPrefix,
int32 InPrefixLen,
ESearchCase::Type SearchCase
)

 Removes the text from the start of the string if it exists.
Public function void Removes spaces from the string. I.E. "Spaces Are Cool" > "SpacesAreCool".
Public function DataType::RangedForReverseIteratorType

rend ()

  
Public function Const DataType::RangedForConstReverseIteratorType

rend ()

  
Public function FString

Replace ( const TCHAR* From,
const TCHAR* To,
ESearchCase::Type SearchCase
)

 Replace all occurrences of a substring in this string
Public function Const FString

Replace ( const TCHAR* From,
const TCHAR* To,
ESearchCase::Type SearchCase
)

 Replace all occurrences of a substring in this string
Public function void

ReplaceCharInline ( const TCHAR SearchChar,
const TCHAR ReplacementChar,
ESearchCase::Type SearchCase
)

 Replace all occurrences of a character with another.no dynamic allocation
Public function FString

ReplaceCharWithEscapedChar ( const TArray< TCHAR >* Chars
)

 Replaces certain characters with the "escaped" version of that character (i.e. replaces "\n" with "\n").
Public function Const FString

ReplaceCharWithEscapedChar ( const TArray< TCHAR >* Chars
)

 Replaces certain characters with the "escaped" version of that character (i.e. replaces "\n" with "\n").
Public function void

ReplaceCharWithEscapedCharInline ( const TArray< TCHAR >* Chars
)

 Replaces certain characters with the "escaped" version of that character (i.e. replaces "\n" with "\n").
Public function Const FString

ReplaceEscapedCharWithChar ( const TArray< TCHAR >* Chars
)

 Removes the escape backslash for all supported characters, replacing the escape and character with the non-escaped version.
Public function FString

ReplaceEscapedCharWithChar ( const TArray< TCHAR >* Chars
)

 Removes the escape backslash for all supported characters, replacing the escape and character with the non-escaped version.
Public function void

ReplaceEscapedCharWithCharInline ( const TArray< TCHAR >* Chars
)

 Removes the escape backslash for all supported characters, replacing the escape and character with the non-escaped version.
Public function int32

ReplaceInline ( const TCHAR* SearchText,
const TCHAR* ReplacementText,
ESearchCase::Type SearchCase
)

 Replace all occurrences of SearchText with ReplacementText in this string.
Public function Const FString Returns a copy of this string with all quote marks escaped (unless the quote is already escaped)
Public function FString Returns a copy of this string with all quote marks escaped (unless the quote is already escaped)
Public function void

Reserve ( int32 CharacterCount
)

 To allow more efficient memory handling, automatically adds one for the string termination.
Public function void

Reset ( int32 NewReservedSize
)

 Empties the string, but doesn't change memory allocation, unless the new size is larger than the current string.
Public function Const FString

Reverse ()

 Returns a copy of this string, with the characters in reverse order
Public function FString

Reverse ()

 Returns this string, with the characters in reverse order
Public function void Reverses the order of characters in this string
Public function Const FString

Right ( int32 Count
)

 Returns the string to the right of the specified location, counting back from the right (end of the word).
Public function FString

Right ( int32 Count
)

  
Public function Const FString

RightChop ( int32 Count
)

 Returns the string to the right of the specified location, counting forward from the left (from the beginning of the word).
Public function FString

RightChop ( int32 Count
)

  
Public function void

RightChopInline ( int32 Count,
bool bAllowShrinking
)

 Modifies the string such that it is now the string to the right of the specified location, counting forward from the left (from the beginning of the word).
Public function void

RightInline ( int32 Count,
bool bAllowShrinking
)

 Modifies the string such that it is now the right most given number of characters
Public function Const FString

RightPad ( int32 ChCount
)

 Pad the right of this string for ChCount characters
Public function Static FString

SanitizeFloat ( double InFloat,
const int32 InMinFractionalDigits
)

 Converts a float string with the trailing zeros stripped For example - 1.234 will be "1.234" rather than "1.234000"
Public function Const void

SerializeAsANSICharArray ( FArchive& Ar,
int32 MinCharacters
)

 Serializes a string as ANSI char array.
Public function void

Shrink ()

 Remove unallocated empty character space from the end of this string
Public function Const bool

Split ( const FString& InS,
FString* LeftS,
FString* RightS,
ESearchCase::Type SearchCase,
ESearchDir::Type SearchDir
)

 Splits this string at given string position case sensitive.
Public function Const bool

Split ( const FString& InS,
FString* LeftS,
FString* RightS
)

 Split with ESearchCase::IgnoreCase and ESearchDir::FromStart.
Public function Const bool

StartsWith ( const FString& InPrefix,
ESearchCase::Type SearchCase
)

 Test whether this string starts with given prefix.
Public function Const bool

StartsWith ( const TCHAR* InPrefix,
ESearchCase::Type SearchCase
)

 Test whether this string starts with given prefix.
Public function Const bool

StartsWith ( const TCHAR* InPrefix,
int32 InPrefixLen,
ESearchCase::Type SearchCase
)

 Test whether this string starts with given prefix.
Public function Const bool

StartsWith ( TCharRangeType&& InPrefix,
ESearchCase::Type SearchCase
)

 Test whether this string starts with given prefix.
Public function Static bool

ToBlob ( const FString& Source,
uint8* DestBuffer,
const uint32 DestSize
)

 Converts a string into a buffer
Public function Const bool

ToBool ()

 Converts a string into a boolean value 1, "True", "Yes", FCoreTexts::True, FCoreTexts::Yes, and non-zero integers become true 0, "False", "No", FCoreTexts::False, FCoreTexts::No, and unparsable values become false
Public function Static bool

ToHexBlob ( const FString& Source,
uint8* DestBuffer,
const uint32 DestSize
)

 Converts a string into a buffer
Public function Const FString

ToLower ()

 Returns a new string with the characters of this converted to lowercase
Public function FString

ToLower ()

 Converts all characters in this rvalue string to lowercase and moves it into the returned string.
Public function void Converts all characters in this string to lowercase
Public function Const FString

ToUpper ()

 Returns a new string with the characters of this converted to uppercase
Public function FString

ToUpper ()

 Converts all characters in this rvalue string to uppercase and moves it into the returned string.
Public function void Converts all characters in this string to uppercase
Public function FString

TrimChar ( const TCHAR CharacterToTrim,
bool* bCharRemoved
)

 Returns a copy of this string with wrapping CharacterToTrim removed (removes at max one instance in the beginning and end of the string).
Public function Const FString

TrimChar ( const TCHAR CharacterToTrim,
bool* bCharRemoved
)

 Returns a copy of this string with wrapping CharacterToTrim removed (removes at max one instance in the beginning and end of the string).
Public function void

TrimCharInline ( const TCHAR CharacterToTrim,
bool* bCharRemoved
)

 Trims a single character from the start and end of the string (removes at max one instance in the beginning and end of the string).
Public function Const FString

TrimEnd ()

 Removes whitespace characters from the end of this string.
Public function FString

TrimEnd ()

 Removes whitespace characters from the end of this string.
Public function void Removes whitespace characters from the end of this string. Modifies the string in-place.
Public function Const FString

TrimQuotes ( bool* bQuotesRemoved
)

 Returns a copy of this string with wrapping quotation marks removed.
Public function FString

TrimQuotes ( bool* bQuotesRemoved
)

 Returns this string with wrapping quotation marks removed.
Public function void

TrimQuotesInline ( bool* bQuotesRemoved
)

 Trims wrapping quotation marks from this string.
Public function Const FString Removes whitespace characters from the start of this string.
Public function FString Removes whitespace characters from the start of this string.
Public function FString Removes whitespace characters from the start and end of this string.
Public function Const FString Removes whitespace characters from the start and end of this string.
Public function void Removes whitespace characters from the start and end of this string. Modifies the string in-place.
Public function void Removes whitespace characters from the start of this string. Modifies the string in-place.
Public function void Trims the inner array after the null terminator.

Operators

  Type Name Description
Public function Const bool

operator!= ( const FString& Rhs
)

 Lexicographically test whether the left string is != the right stringcase insensitive
Public function Const bool

operator!= ( const CharType* Rhs
)

 Lexicographically test whether the left string is != the right stringcase insensitive
Public function Const const TCHAR * Get pointer to the stringPointer to Array of TCHAR if Num, otherwise the empty string
Public function FString &

operator/= ( CharRangeType&& Str
)

 Concatenate this path with given path ensuring the / character is used between them
Public function FString &

operator/= ( const CharType* Str
)

 Concatenate this path with given path ensuring the / character is used between them
Public function FString &

operator/= ( const TCHAR* Str
)

 Concatenate this path with given path ensuring the / character is used between them
Public function Const const TCHAR &

operator[] ( int32 Index
)

 Return specific const character from this string
Public function TCHAR &

operator[] ( int32 Index
)

 Return specific character from this string
Public function FString &

operator+= ( AppendedCharType Char
)

 Append a single character and return a reference to this
Public function auto

operator+= ( StrType&& Str
)

 Append a string and return a reference to this
Public function FString &

operator= ( CharRangeType&& Range
)

  
Public function FString &

operator= ( const TCHAR* Str
)

  
Public function FString &

operator= ( const FString&
)

  
Public function FString &  
Public function Const bool

operator== ( const CharType* Rhs
)

 Lexicographically test whether the left string is == the right stringcase insensitive
Public function Const bool

operator== ( const FString& Rhs
)

 Lexicographically test whether the left string is == the right stringcase insensitive

Typedefs

Name Description
AllocatorType  
DataType Array holding the character data
ElementType  
TConstIterator  
TIsCharRangeNotCArray Trait testing whether a type is a contiguous range of characters, and not CharType[].
TIsCharRangeNotCArrayNotFString Trait testing whether a type is a contiguous range of characters, and not CharType[] and not FString.
TIsTCharRangeNotCArray Trait testing whether a type is a contiguous range of TCHAR, and not TCHAR[].
TIsTCharRangeNotCArrayNotFString Trait testing whether a type is a contiguous range of TCHAR, and not TCHAR[] and not FString.
TIterator Iterator typedefs
TRangeElementType  

See Also

https://docs.unrealengine.com/latest/INT/Programming/UnrealArchitecture/StringHandling/FString/

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