有多列数据, 序号, 学校, 课程 … 年份这几列。要如果学校和课程相同就根据年份倒序排列。
先按学校排序, 再按课程排序, 然后按年份倒序排序。
我定义一个类来进行多列数据的排序, 很方便：
class Course {
has Int $.numb;
has Str $.univ;
has Str $.dis;
has Int $.paper;
has Int $.cited;
has Int $.year;
}
my @headers = <numb univ dis paper cited year>;
my @courses;
for $=finish.lines -> $line {
next if $line ~~ /^num/;
my @words = $line.words;
@words[0, 3,4,5] = @words[0,3,4,5]».Int;
my %h = @headers Z=> @words;
my $course = Course.new(|%h);
@courses.push($course);
}
my @sorted = @courses.sort(*.univ).sort(*.dis).sort(-*.year);
for @sorted {
say join " ", .numb, .univ, .dis, .paper, .cited, .year;
}
=finish
num univ dis paper cited year
1 Beijing Physics 193 4555 2005
2 Beijing Physics 197 2799 2006
3 Beijing Physics 240 2664 2007
4 Beijing Physics 200 3191 2008
5 Beijing Physics 268 2668 2009
6 Beijing Physics 249 2300 2010
7 Beijing Physics 262 2080 2011
8 Beijing Physics 230 2371 2012
9 Beijing Physics 309 1367 2013
10 Beijing Physics 284 615 2014
11 Beijing Chemistry 143 1650 2005
12 Beijing Chemistry 149 2379 2006
13 Beijing Chemistry 190 2566 2007
14 Beijing Chemistry 147 1888 2008
15 Beijing Chemistry 184 2146 2009
16 Beijing Chemistry 214 2568 2010
17 Beijing Chemistry 238 2874 2011
18 Beijing Chemistry 265 2097 2012
19 Beijing Chemistry 251 1303 2013
20 Beijing Chemistry 241 656 2014
