Transcript Week 2 Slides

Programming Perl in UNIX
Course Number : CIT 370
Week 2
Prof. Daniel Chen
Introduction
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Review and Overviews
Chapter 4
Summary
Lab
Quiz 1
Next Week (Week 3)
Topics of Discussion
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About Perl Variables
Scalars, Arrays, and Hashes
Reading from STDIN
Array Functions
Hash (Associative Array) Functions
More Hashes
Chapter 4: What’s in a Name
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4.1 About Perl Variables
4.2 Scalars, Arrays, and Hashes
4.3 Reading from STDIN
4.4 Array Functions
4.5 Hash (Associative Array) Functions
4.6 More Hashes
4.1 About Perl variables
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4.1.1 Types
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4.1.2 Scope and the Package
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Scalar, Array, Hashes
Package, Global Variables
4.1.3 Naming Conventions
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Case Sensitive
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4.1.4 Assignment Statements
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4.1.5 Quoting Rules
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Single quotes
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Double Quotes
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Back Quotes
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Perl’s Alternative Quotes (Table 4.1)
4.2 Scalars, Arrays, and Hashes
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4.2.1 Scalar Variables
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Assignment
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The undef Function
4.2.2 Arrays
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Special Scalars and Array Assignment
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Accessing Elements
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Array Slices
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Multi-dimension Arrays – Lists of Lists
4.2.3 Hashes
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Accessing Elements
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Hash Slices
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Hashes of Hashes
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Array of Hashes
4.3 Reading From STDIN
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4.3.1 Assigning Input to a Scalar Variable
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4.3.2 The chop and chomp Functions
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4.3.3 The read Function
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4.3.4 The getc Function
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4.3.5 Assigning Input to an Array
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4.3.6 Assigning Input to a Hash
4.4 Array Functions
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The chop and chomp Functions (with Lists)
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The exists Function
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The delete Function
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The grep Function
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The join Function
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The map Function
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The pack and unpack Functions
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The pop Function
Array Functions
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The push Function
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The shift Function
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The delete Function
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The splice Function
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The split Function
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The sort Function
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The reverse Functions
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The unshift Function
4.5 Hash (Associative Array) Functions
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The keys Function
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The values Function
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The each Function
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The delete Function
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The exists Function
4. 6 More Hashes
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4.6.1 Loading a Hash from a File
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4.6.2 Special Hashes
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The %ENV hash
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The %SIG Hash
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The %INC Hash
4.6.3 Context
Matching a string or character at
the beginning of a line with a ^
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using the ^ allows you to match words or
characters at the beginning of the line only.
Two examples
- ls -l ^d
- ^…4XC….
Matching a string or character at
the end of a line with a $
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The $ lets us match a string or character at the
end of the line
Two examples
- trouble$
- jet01$
Matching a single or string or
character with *
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The * allows us to match repeatedly
any number of occurrences of any
character or string
Two examples
- compu*t (computer, computing,
compuuuuuute)
- 10133* (1013333, 10133, 1013444444)
Escaping the meaning of a
special character with \
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Special characters ($ . “ * [ ] | () \ +
?)
To disable the special character
- Using \.
- Using \*\.pas (*.pas)
Matching ranges or sets using []
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To match certain specific characters or range of
characters use []
Examples
- [0-9] or [a-z]
- [A-Za-z]
- [A-Za-z0-9]
- s[a-zA-Z]t
- [Cc]omputer
- [^a-zA-Z]
Matching a specific number of
occurrences with \{\}
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If you want to match only a certain number of
occurrences, you can use \{ \}
pattern \{n\} (match n occurrences of the pattern)
pattern \[n,\} (match at least n occurrences of the pattern)
pattern \{n,m\} (match occurrences of the pattern between
n and m, where n and m are integer numbers between 0
and 255)
Examples
- A\{2\}B (AAB)
- A\{4,\}B (AAAAAB)
- A\{2,4\}B (2 As or 4As)
Summary
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Perl Variables
Scalars, Arrays, and Hashes
Reading from STDIN
Array Functions
Hash Functions
Special Characters
Lab
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Examples 4.1 – 4.59 (P 43 – 97)
Homework 2
Quiz 1
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Quiz Date: Next Week
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Quiz Time: 11:00 AM - 11:30 AM
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Contents: Chapter 1- Chapter 4
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No book, no note, no computer
Next Week
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Reading assignment (Textbook
chapters 5 and 6)