1. 题目
2. 代码与输出
1 # -----------------------------------------------------------# 2 # Source: Learning Perl, chapter9,exercise-1 3 # Date: 2012-01-19 4 # Author: xiaodongrush 5 #-----------------------------------------------------------# 6 use 5.010; 7 @array = qw { 8 fredfredfred 9 fredfredbarney 10 barneyfredfred 11 barneybarneybarney 12 fred|barney 13 }; 14 @content = qw { 15 fred fred|barney 16 }; 17 foreach $what( @content) { 18 say " \$what = $what "; 19 say " \@array = (@array) "; 20 foreach $text( @array) { 21 if( $text =~ m/(?: $what){ 3}/) { 22 say " <$`><$&><$'> "; 23 } 24 } 25 say " ---------------------------- "; 26 } 27 <STDIN>; 28 # -----------------------------------------------------------# 29 # 将某个字符串重复3次，注意这个字符串可能包含或|这样的字符，因此将其用括号 30 # 括起来就好了 31 #-----------------------------------------------------------#
1 # -----------------------------------------------------------# 2 # Source: Learning Perl, chapter9,exercise-2 3 # Date: 2012-01-19 4 # Author: xiaodongrush 5 #-----------------------------------------------------------# 6 use 5.010; 7 $input_file = $ARGV[ 0]; 8 $output_file = $ARGV[ 0] . " .out "; 9 unless(! open IN, " <$input_file ") { 10 say " Can't read <$input_file> ! "; 11 } 12 unless( open OUT, " >$output_file ") { 13 say " Can't write <$output_file> ! "; 14 } 15 while(<IN>) { 16 s/Fred/Larry/gi; 17 print OUT $_; 18 } 19 # -----------------------------------------------------------# 20 # 只读<，只写>，追加写>>，默认就是读写 21 #-----------------------------------------------------------#
1 # -----------------------------------------------------------# 2 # Source: Learning Perl, chapter9,exercise-3 3 # Date: 2012-01-19 4 # Author: xiaodongrush 5 #-----------------------------------------------------------# 6 use 5.010; 7 $text = " fred&wilma&fred&wilma&fred&wima "; 8 say " text = $text "; 9 @array = split /fred/gi, $text; 10 foreach( @array) { 11 s/wilma/Fred/gi; 12 } 13 $text = join Wilma, @array; 14 say " text = $text "; 15 <STDIN>; 16 # -----------------------------------------------------------# 17 #1.该解法是用Fred作为分割符，将字符串分开，然后，将分开的 18 # 字符串中的wilma环卫Fred，然后再用Wilma将分开的字符串连起来 19 #2.书中解法是，首先对字符串chomp，保证不含\n，然后将Fred都换为 20 # \n，接着讲Wilma都换为Fred，最后将\n都换为Wilma 21 #-----------------------------------------------------------#
1 # -----------------------------------------------------------# 2 # Source: Learning Perl, chapter9,exercise-4 3 # Date: 2012-01-19 4 # Author: xiaodongrush 5 #-----------------------------------------------------------# 6 use 5.010; 7 $^I = " .bak "; 8 $text = " ## Copyright (C) 2012 by Yours Truly\n "; 9 while(<>) { 10 if(/ # !/) { 11 $_ = $_ . $text; 12 } 13 print $_; 14 } 15 # -----------------------------------------------------------# 16 # 1. /i表示忽略大小写，/g表示全局匹配 17 # 2. $^I，在读入文件假设是word.txt，首先将其改名为word.txt.out， 18 # 然后创建一个空的word.txt文件，接着，word.txt.out的每一行， 19 # 并且通过print函数写入到word.txt文件中。 20 #-----------------------------------------------------------#
1 # -----------------------------------------------------------# 2 # Source: Learning Perl, chapter9,exercise-4 3 # Date: 2012-01-19 4 # Author: xiaodongrush 5 #-----------------------------------------------------------# 6 use 5.010; 7 $text = " ## Copyright (C) 2012 by Yours Truly\n "; 8 foreach( @ARGV) { 9 $files{ $_} = 1; 10 } 11 while(<>) { 12 if(/ # # Copyright/) { 13 delete $files{ $ARGV}; 14 } 15 } 16 @ARGV = keys %files; 17 $^I = " .bak "; 18 if( @ARGV != 0) { 19 while(<>) { 20 if(/ # !/) { 21 $_ = $_ . $text; 22 } 23 print $_; 24 } 25 } 26 # -----------------------------------------------------------# 27 # 1. /i表示忽略大小写，/g表示全局匹配 28 # 2. $^I，在读入文件假设是word.txt，首先将其改名为word.txt.out， 29 # 然后创建一个空的word.txt文件，接着，word.txt.out的每一行， 30 # 并且通过print函数写入到word.txt文件中。 31 #-----------------------------------------------------------#
输出略，与前一题类似。
3. 文件