Ruby: each_byte method

Question

I need to use the each_byte method on a given string and format it properly.

The string I am working with is stored in the variable the_string, and contains the following characters (whitespace and numbers are part of the string):

1.               this string has leading space and too    "MANY tabs and sPaCes betweenX"

The output I am looking for, when formatted properly, should look like this:

----------
C|Dec|Hex
----------
1| 49|0x31
.| 46|0x2E
 | 32|0x20
 | 32|0x20
 | 32|0x20
 | 32|0x20
 | 32|0x20
 | 32|0x20
 | 32|0x20
 | 32|0x20
 | 32|0x20
 | 32|0x20
 | 32|0x20
 | 32|0x20
 | 32|0x20
 | 32|0x20
 | 32|0x20
t|116|0x74
h|104|0x68
i|105|0x69
s|115|0x73
 | 32|0x20
s|115|0x73
t|116|0x74
r|114|0x72
i|105|0x69
n|110|0x6E
g|103|0x67
 | 32|0x20

However, when I use

puts the_string.each_byte {|c| print c, ' ' }

I get a result that looks like this:

49 46 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 116 104 105 115 32 115 116 114 105 110 103 32 104 97 115 32 108 101 97 100 105 110 103 32 115 112 97 99 101 32 97 110 100 32 116 111 111 32 32 32 32 34 77 65 78 89 32 116 97 98 115 32 97 110 100 32 115 80 97 67 101 115 32 98 101 116 119 101

How can I format my result so that it prints the original character, the decimal value, and the hex value in a column format as shown above? I looked through the documentation and am not able to find details on how to use each_byte. Any help is appreciated!

ruby-doc.org/core-2.2.0/String.html#method-i-each_byte, though you might be interested in ruby-doc.org/core-2.2.0/String.html#method-i-each_char and ruby-doc.org/core-2.2.0/String.html#method-i-ord. Also ruby-doc.org/core-2.2.0/Fixnum.html#method-i-to_s. — Reinstate Monica -- notmaynard
– Reinstate Monica -- notmaynard, Commented Jan 22, 2015 at 23:47
Why do you say you need to use the methodeach_byte? If this is an assignment, that's fine, but of course there are ways to construct the desired table without the use of that method. For example, as an exercise, try this: puts the_string.gsub(/./) { |c| ???? }. — Cary Swoveland
– Cary Swoveland, Commented Jan 23, 2015 at 0:26

sled · Accepted Answer · 2015-01-23 00:01:47Z

1

You have multiple choices here, for hexadecimal you can either use sprintf or the good old to_s and specifying the radix to be base 16, here's an example:

a = "YOUR STRING WHICH IS WAY TOO LONG TO FORMAT PROPERLY ON STACKOVERFLOW"

# Output is:
# chr | ord | hex

# using sprintf
a.each_byte do |byte|
    puts [byte.chr, byte.to_s, ("0x%02X" % byte)].join("\t")
end

# using to_s(16) which will use base-16 
a.each_byte do |byte|
    puts [byte.chr, byte.to_s, "0x#{byte.to_s(16).upcase}"].join("\t")
end

Note on the side: Be aware of multibyte characters.

edited Jan 23, 2015 at 0:01

answered Jan 22, 2015 at 23:54

sled

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2 Comments

amoeboar Over a year ago

Worked for me, thank you. I am only still confused as to why the part ("0x%02X" % byte) produces the appropriate hex values.

sled Over a year ago

%02X is the actual formatting template for printf, and the % operator in conjunction with a string is just a short-hand syntax for printf. Detailed infos can be found on RubyDoc

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