Non-decimal radices/Convert: Difference between revisions
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(→{{header|Ruby}}: Since Ruby 1.9.3, Integer takes a second argument (base) and is strict (errors fast).) |
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=={{header|Ruby}}== |
=={{header|Ruby}}== |
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This converts strings from any base to any base up to base 36. |
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<lang ruby>s = 26.to_s(16) # returns the string 1a |
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i = '1a'.to_i(16) # returns the integer 26</lang> |
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def convert_base(from, to) |
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Caution: <tt>to_i</tt> simply stops when it reaches an invalid character; it does not raise any exceptions. So sometimes it may appear to parse something and get a result, but it is only based on part of the input string: |
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Integer(self, from).to_s(to) |
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<lang ruby>"59".to_i(7) # returns 5, but this is probably not what you wanted</lang> |
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# self.to_i(from).to_s(to) #if you don't want exceptions |
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For a general base parsing that raises an exception for invalid characters: |
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{{trans|Tcl}} |
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DIGITS = [*"0".."9", *"a".."z"] |
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def baseconvert(str, basefrom, baseto) |
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dec2base(base2dec(str, basefrom), baseto) |
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end |
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def base2dec(str, base) |
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raise ArgumentError, "base is invalid" unless base.between?(2, DIGITS.length) |
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str.to_s.downcase.each_char.inject(0) do |res, c| |
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idx = DIGITS[0,base].index(c) |
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idx.nil? and raise ArgumentError, "invalid base-#{base} digit: #{c}" |
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res = res * base + idx |
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end |
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end |
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def dec2base(n, base) |
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return "0" if n == 0 |
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raise ArgumentError, "base is invalid" unless base.between?(2, DIGITS.length) |
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res = [] |
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while n > 0 |
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n, r = n.divmod(base) |
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res.unshift(DIGITS[r]) |
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end |
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res.join |
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end |
end |
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end |
end |
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# first three taken from TCL |
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include BaseConvert |
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p |
p "12345".convert_base(10, 23) # "107h" |
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p "107h".convert_base(23, 7) # "50664" |
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p base2dec("1a", 16) # => 26 |
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p "50664".convert_base(7, 10) # "12345" |
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p baseconvert("107h", 23, 7) # => "50664"</lang> |
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p "ff".convert_base(15, 10) # => ArgumentError</lang> |
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=={{header|Run BASIC}}== |
=={{header|Run BASIC}}== |
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