␡
- 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
2.2 Representing Strings with Alternate Notations
Sometimes we want to represent strings that are rich in metacharacters, such as single quotes, double quotes, and more. For these situations, we have the %q and %Q notations. Following either of these is a string within a pair of delimiters; I personally favor square brackets ([]).
The difference between the %q and %Q variants is that the former acts like a single-quoted string, and the latter like a double-quoted string:
S1 = %q[As Magritte said, "Ceci n'est pas une pipe."] s2 = %q[This is not a tab: (\t)] # same as: 'This is not a tab: \t' s3 = %Q[This IS a tab: (\t)] # same as: "This IS a tab: \t"
Both kinds of notation can be used with different delimiters. Besides brackets, there are other paired delimiters (parentheses, braces, and angle brackets):
s1 = %q(Bill said, "Bob said, 'This is a string.'")
s2 = %q{Another string.}
s3 = %q<Special characters '"[](){} in this string.>
There are also “nonpaired” delimiters. Basically any character may be used that is printable, but not alphanumeric, not whitespace, and not a paired character:
s1 = %q:"I think Mrs. O'Leary's cow did it," he said.: s2 = %q*\r is a control-M and \n is a control-J.*