Perl-Chapter 3-list and array-Exercises

1. Question

2. Code

1 #-----------------------------------------------------------#
2 # Source: Learning Perl, chapter3
3 # Date: 2012-01-13
4 # Author: xiaodongrush
5 #-----------------------------------------------------------#
6 # code-1 #
7 #-----------------------------------------------------------#
8 $ split = "-------------------------------------------------";
9 $ code1 = 'chomp (@ strs = <STDIN>); '. "\ n ".
10 'foreach (reverse (@ strs) {'. "\ n ".
11 'print $ _. "\ n"; '. "\ n ".
12 '}';
13 print "code-1 \ n". $ code1. "\ n". $ split;
14 #-----------------------------------------------------------#
15 # execute-1 #
16 #-----------------------------------------------------------#
17 print "\ nexecute-1 \ n ";
18 chomp (@ STRs = <stdin> );
19 foreach (reverse (@ STRs )){
20 Print $ _. "\ n ";
21}
22 #-----------------------------------------------------------#
23 # code-2 #
24 #-----------------------------------------------------------#
25 $ code2 = '@ names = QW {Fred Betty Barney Dino Wilma pebbles Bamm-Bamm};'. "\ n ".
26 'chomp (@ indexes = <STDIN>); '. "\ n ".
27 'foreach (@ indexes) {'. "\ n ".
28 'print @ names [($ _-1) % 7]. "\ n"; '. "\ n ".
29 '}';
30 print $ split. "\ ncode-2 \ n". $ code2. "\ n". $ split;
31 #-----------------------------------------------------------#
32 # execute-2 #
33 #-----------------------------------------------------------#
34 print "\ nexecute-2 \ n ";
35 @ names = qw {fred betty barney dino wilma pebbles bamm-bamm };
36 chomp (@ indexes = <STDIN> );
37 foreach (@ indexes ){
38 print @ names [($ _-1) % 7]. "\ n ";
39}
40 #-----------------------------------------------------------#
41 # code-3 #
42 #-----------------------------------------------------------#
43 $ code3 = 'chomp (@ strs = <STDIN>); '. "\ n ".
44 'foreach (sort (@ strs) {'. "\ n ".
45 'print $ _. ""; '. "\ n ".
46 '}'. "\ n ".
47 'print "\ n"; '. "\ n ".
48 'foreach (sort (@ strs) {'. "\ n ".
49 'print $ _. "\ n"; '. "\ n ".
50 '}';
51 print $ split. "\ ncode-3 \ n". $ code3. "\ n". $ split;
52 #-----------------------------------------------------------#
53 # execute-3 #
54 #-----------------------------------------------------------#
55 print "\ nexecute-3 \ n ";
56 chomp (@ STRs = <stdin> );
57 foreach (sort (@ STRs )){
58 Print $ _."";
59}
60 print "\ n ";
61 foreach (sort (@ STRs )){
62 Print $ _. "\ n ";
63}
64 #-----------------------------------------------------------#
65 print "end !!! ";
66 <STDIN>
67 #-----------------------------------------------------------#
68 # conclusion
69 #1. @ str_array = <STDIN>; each time a row is read, an element is added to the array,
70 # Until the Read File is empty or enter Control + Z (Windows), Control + D (Unix)
71 #2. $ _ indicates variables with omitted parameters, such as foreach () and print.
72 #3. reverse, sort, these functions are different from chomp, more like the return value, while chomp directly modifies the original array or the original variable

3. Output

4. File

/Files/pangxiaodong/learns ningperl/ch3-answer.rar