char2num {lazy.tools}

R Documentation

Convert a Character Vector to a List of Numeric Vectors or vice versa via raw expression.

Description

Convert a Character Vector to a List of Numeric Vectors or vice versa via raw expression.

Usage

char2num(char)

num2char(num)

Arguments

char	a vector of strings
num	a list of numeric vectors or a numeric vector which can be converted to string via raw conversion.

Details

Since these functions can handle multi byte characters,
they can be used to store the strings with multi byte characters as a list of numeric vectors.

The core part of these functions are:
char to num

 num <- as.numeric( charToRaw(char) )

num to char

char <- rawToChar( as.raw( num ) )

The numbers and Raw expression are related as

 num <- char2num( char )
 ( hex <- as.hexmode( num ) )
 print( as.raw(num) )

Value

char2num
If char is a string ( a vector of length 1 ), num is a vector.
If char is a vector of strings, num is a list of length(char)

num2char
If num is a vector, char is a string.
If num is a list, char is a vector of strings of length(num)

Examples

# char is a string
( char <- "This is an example." )
( num <- char2num( char ) )
( is.numeric(num) )
( char2 <- num2char( num ) )

# char is a string vector
( char2 <- c("This is an example.", "2nd line") )
( num2 <- char2num( char2 ) )
( sapply( num2, is.numeric ) )
( char22 <- num2char( num2 ) )

# storing multi byte characters in a package: \cr
# See the description of 'generate_zenkaku_sets'.
{if( regexpr("utf8",Sys.getlocale (category = "LC_CTYPE")) > 0 )
 nn <- c(87, 101,  32, 104,  97, 118, 101,  32, 228, 184, 141, 232, 184
         , 176, 231, 159, 169,  32, 121, 101, 116,  33)
else
 nn <- c(87, 101,  32, 104,  97, 118, 101,  32, 149, 115, 230, 250, 139
         , 233, 32, 121, 101, 116,  33)}
( zz <- num2char(nn) )
( zzh <- as.hexmode(nn) )
charToRaw(zz)

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