R/string.r

In APSIMBatch: Analysis the output of Apsim software

# * Author:    Bangyou Zheng (Bangyou.Zheng@csiro.au)
# * Created:   06/04/2010
# *
# * $Revision: 2371 $
# * $Id: string.r 2371 2011-07-19 10:57:29Z zhe00a $
# * $Author: zhe00a $
# * $Date: 2011-07-19 20:57:29 +1000 (Tue, 19 Jul 2011) $

#' Get the length of a string
#'
#' @param str Input string
#' @return The character number of the string
len <- function( str )
{
	return( length( unlist( strsplit( str, "" ) ) ) )
}

#' Get the several characters of a string from left
#'
#' @param str Input string
#' @param num The number of character will be returned from left
#' @return the character vector of the string from left
left <- function( str, num = 1 )
{
	return( substr( str, 1, num ) ) 
}

#' Get the several characters of a string from right
#'
#' @param str Input string
#' @param num The number of character will be returned from right
#' @return the character vector of the string from right
right <- function( str, num = 1 )
{
	len =  len( str )
	return( substr( str, len - num + 1, len ) )
}

#' Omit the blank of a string
#'
#' @param str Input string
#' @return the character vector except the blank
omitBlank <- function( str )
{
	str <- unlist( strsplit( str, "" ) )
	str[str==" "] <- ""
	res <- NULL
	for ( i in 1:length(str) )
	{
		res <- paste( res, str[i], sep = "" )
	}
	return( res )
}
#' Search a character from a string
#'
#' @param str Input string
#' @param search The character will be searched
#' @param start The start position to search
#' @return The postion where character firstly appear 
searchChar <- function( str, search, start = 1 )
{
	str <- unlist( strsplit( str, "" ) )
	pos <- NULL
	for ( i in start:length(str) )
	{
		if ( str[i] == search )
		{
			pos <- i
			break
		}
	}
	return( pos )
}

#' Omit the start and end blank charcter
#'
#' @param str Input string
#' @return the character vector except the blank at the start and end
omitBlankSE <- function( str )
{
	str <- unlist( strsplit( str, "" ) )
	for ( i in 1:length(str) )
	{
		if ( str[i] != " " )
		{

			str <- str[ i:length( str ) ]
			break
		}
		
	}
	for ( i in length(str):1 )
	{
		if ( str[i] != " " )
		{
			str <- str[ 1:i ]
			break
		}
		
	}
	res <- NULL
	for ( i in 1:length(str) )
	{
		res <- paste( res, str[i], sep = "" )
	}
	return( res )
}

#' Convert vector to string
#'
#' Convert vertor to string with a separater
#' @param vector The input vector to convert
#' @param sep The separater with default value ", "
#' @return The string which connected all members of vector
vector2string <- function( vector, sep = ", " )
{
	s <- as.character( vector[1] )
	if ( length( vector ) > 1 )
	{
		for ( i in 2:length( vector ) )
		{
			s <- paste( s, vector[i], sep = sep )
		}
	}
	return( s )
}

#' Split a string contained a equal mark
#'
#' @param vector The input vector to convert
#' @return the variable name and value
splitEqual <- function( vector )
{
	pos <- searchChar( vector, "=" )
	
	name <- omitBlankSE( left( vector, pos - 1 ) )
	value <- omitBlankSE( right( vector, len( vector ) - pos ) )
	
	res <- list( name = name, value = value )
	return( res )
}