␡
- 2.1 Representing Ordinary Strings
- 2.2 Representing Strings with Alternate Notations
- 2.3 Using Here-Documents
- 2.4 Finding the Length of a String
- 2.5 Processing a Line at a Time
- 2.6 Processing a Character or Byte at a Time
- 2.7 Performing Specialized String Comparisons
- 2.8 Tokenizing a String
- 2.9 Formatting a String
- 2.10 Using Strings as IO Objects
- 2.11 Controlling Uppercase and Lowercase
- 2.12 Accessing and Assigning Substrings
- 2.13 Substituting in Strings
- 2.14 Searching a String
- 2.15 Converting Between Characters and ASCII Codes
- 2.16 Implicit and Explicit Conversion
- 2.17 Appending an Item onto a String
- 2.18 Removing Trailing Newlines and Other Characters
- 2.19 Trimming Whitespace from a String
- 2.20 Repeating Strings
- 2.21 Embedding Expressions within Strings
- 2.22 Delayed Interpolation of Strings
- 2.23 Parsing Comma-Separated Data
- 2.24 Converting Strings to Numbers (Decimal and Otherwise)
- 2.25 Encoding and Decoding <tt>rot13</tt> Text
- 2.26 Encrypting Strings
- 2.27 Compressing Strings
- 2.28 Counting Characters in Strings
- 2.29 Reversing a String
- 2.30 Removing Duplicate Characters
- 2.31 Removing Specific Characters
- 2.32 Printing Special Characters
- 2.33 Generating Successive Strings
- 2.34 Calculating a 32-Bit CRC
- 2.35 Calculating the SHA-256 Hash of a String
- 2.36 Calculating the Levenshtein Distance Between Two Strings
- 2.37 Encoding and Decoding Base64 Strings
- 2.38 Expanding and Compressing Tab Characters
- 2.39 Wrapping Lines of Text
- 2.40 Conclusion
This chapter is from the book
This chapter is from the book
This chapter is from the book
This chapter is from the book
2.38 Expanding and Compressing Tab Characters
Occasionally we have a string with tabs in it and we want to convert them to spaces (or vice versa). The two methods shown here do these operations:
class String
def detab(ts=8)
str = self.dup
while (leftmost = str.index("\t")) != nil
space = " "*(ts-(leftmost%ts))
str[leftmost]=space
end
str
end
def entab(ts=8)
str = self.detab
areas = str.length/ts
newstr = ""
for a in 0..areas
temp = str[a*ts..a*ts+ts-1]
if temp.size==ts
if temp =~ / +/
match=Regexp.last_match[0]
endmatch = Regexp.new(match+"$")
if match.length>1
temp.sub!(endmatch,"\t")
end
end
end
newstr += temp
end
newstr
end
end
foo = "This is only a test. "
puts foo
puts foo.entab(4)
puts foo.entab(4).dump
Note that this code is not smart enough to handle backspaces.