Unreal Engine4 UE4中的字符串转换FString to FName Int32 Float

字符串转化

1. FString to FName
2. std::string to FString
3. FString and FCString Overview
4. FString to Integer
5. FString to Float
6. Float/Integer to FString
7. UE4 C++ Source Header References

All the header files I refer to in this tutorial are found in

your UE4 install directory  / Engine / Source

you will probably want to do a search for them from this point :)

Converting FString to FNames

Say we have

FString TheString = "UE4_C++_IS_Awesome";

To convert this to an FName you do:

FName ConvertedFString = FName(*TheString);

std::string to FString

#include 
 
//....
 
some function
{
  std::string TestString = "Happy"; 
  FString HappyString(TestString.c_str());
}

FString to std::string

#include 
 
//....
FString UE4Str = "Flowers";
std::string MyStdString(TCHAR_TO_UTF8(*UE4Str));

FCString Overview

Converting FString to Numbers

The * operator on FStrings returns their TCHAR* data which is what FCString functions use.

If you cant find the function you want in FStrings (UnrealString.h) then you should check out the FCString functions (CString.h)

I show how to convert from FString to FCString below:

Say we have

FString TheString = "123.021";

FString to Integer

int32 MyShinyNewInt = FCString::Atoi(*TheString);

FString to Float

float MyShinyNewFloat = FCString::Atof(*TheString);

Note that Atoi and Atof are static functions, so you use the syntax FCString::TheFunction to call it :)

Float/Integer to FString

FString NewString = FString::FromInt(YourInt);
 
FString VeryCleanString = FString::SanitizeFloat(YourFloat);

Static functions in the UnrealString.h :)

UE4 Source Header References

CString.h
UnrealString.h
NameTypes.h

See CString.h for more details and other functions like

atoi64 (string to int64)
Atod	(string to double precision float)

For a great deal of helpful functions you will also want to look at

UnrealString.h for direct manipulation of FStrings!

For more info on FNames check out

 NameTypes.h

Enjoy!

------------------------------------------------------------------------------

FArrayReaderPtr to FString

 uint8 data[512];
 FMemory::Memzero(data, 512);

 FMemory::Memcpy(data, ArrayReaderPtr->GetData(), ArrayReaderPtr->Num());
 FString str = ((const char*)data);

Array to FString

 TArray content;
 ...
 const std::string cstr(reinterpret_cast<const char*>(content.GetData()), content.Num());
 FString frameAsFString = cstr.c_str();
 UE_LOG(VRSLog, Warning, TEXT("%s"), *frameAsFString);

FString to char *  TCHAR_TO_ANSI()

 int BP_GetColumnIndex(int resultSet, FString columnName)
 {
     return GetColumnIndex(resultSet, TCHAR_TO_ANSI(*columnName));
 }

 int GetColumnIndex(int iResult, const char* columnName)
 {
 }

FString to TCHAR *

 int BP_GetColumnIndex(int resultSet, FString columnName)
 {
     return GetColumnIndex(resultSet, *columnName);
 }

 int GetColumnIndex(int iResult, const TCHAR* columnName)
 {
 }