FileReadString
FileReadString
The function reads a string from the current position of a file pointer in a file.
string FileReadString(
int file_handle, // File handle
int length=0 // Length of the string
);Parameters
- file_handle
[in] File descriptor returned by FileOpen().
- length=0
[in] Number of characters to read.
Return Value
Line read (string).
Note
When reading from a bin-file. the length of a string to read must be specified. When reading from a txt-file the string length is not required, and the string will be read from the current position to the line feed character “\r\n”. When reading from a csv-file, the string length isn’t required also, the string will be read from the current position till the nearest delimiter or till the text string end character.
If the file is opened with FILE_ANSI flag, then the line read is converted to Unicode.
Example (the file obtained after executing the example for FileWriteInteger() function is used here)
//--- display the window of input parameters when launching the script
#property script_show_inputs
//--- parameters for data reading
input string InpFileName="Trend.bin"; // file name
input string InpDirectoryName="Data"; // directory name
//+------------------------------------------------------------------+
//| Script program start function |
//+------------------------------------------------------------------+
void OnStart()
{
//--- open the file
ResetLastError();
int file_handle=FileOpen(InpDirectoryName+"//"+InpFileName,FILE_READ|FILE_BIN|FILE_ANSI);
if(file_handle!=INVALID_HANDLE)
{
PrintFormat("%s file is available for reading",InpFileName);
PrintFormat("File path: %s\\Files\\",TerminalInfoString(TERMINAL_DATA_PATH));
//--- additional variables
int str_size;
string str;
//--- read data from the file
while(!FileIsEnding(file_handle))
{
//--- find out how many symbols are used for writing the time
str_size=FileReadInteger(file_handle,INT_VALUE);
//--- read the string
str=FileReadString(file_handle,str_size);
//--- print the string
PrintFormat(str);
}
//--- close the file
FileClose(file_handle);
PrintFormat("Data is read, %s file is closed",InpFileName);
}
else
PrintFormat("Failed to open %s file, Error code = %d",InpFileName,GetLastError());
}