1 #ex1:向量求和函数 2 my @ex1=1..5; 3 print &sum(\@ex1),"\n"; 4  5 sub sum{ 6     my($vec)=@_; 7     my $result=0; 8     foreach(@$vec){ 9         $result+=$_;10         }11     return $result;12 }13 14 #ex2:向量均值函数15  my @ex2=1..5;16  print &mean(\@ex2),"\n";17 18 sub mean{19     my($vec)=@_;20     my $sum=0;21     foreach(@$vec){22         $sum+=$_;23     }24     my $result=$sum/(scalar @$vec);25     return $result;26 }27 28 29 #ex3:向量样本方差函数30 my @ex3=1..5;31 print &var(\@ex3),"\n";32 33 sub var{34     my($vec)=@_;35     my $m=&mean($vec);36     my $length=scalar @$vec;37     my @squre=map(($_-$m)*($_-$m),@$vec);38     my $result=1/($length-1)*&sum(\@squre);39     return $result;40 }41 42 #ex4:向量样本标准差函数43 my @ex4=1..5;44 print &sd(\@ex4),"\n";45 46 sub sd{47     my($vec)=@_;48     my $result=sqrt(&var($vec));49     return $result;50 }51 52 #ex5:求相关系数53 my @ex51=(2,3,4,9,10);54 my @ex52=1..5;55 print &corr(\@ex51,\@ex52),"\n";56 57 sub corr{58     my($v1,$v2)=@_;59     my $s=0;60     my $length=scalar @$v1;61     my $m1=&mean($v1);62     my $m2=&mean($v2);63     for(my $i=0;$i<$length;$i++){64             $s+=($v1->[$i]-&mean($v1))*($v2->[$i]-&mean($v2));65         }66     my $result=$s/(&sd($v1)*&sd($v2)*($length-1));67     return $result;68 }69 70 71 #求偏度系数 72 my @ex6=(2,3,4,9,10,12);73 print &skew(\@ex6),"\n";74 75 sub skew{76     my($vec)=@_;77     if(scalar @$vec<3){78         die "vector length must be larger than 3!";79     }else{80         my $m=&mean($vec);81         my $n=scalar @$vec;82         my @power=map(($_-$m)*($_-$m)*($_-$m),@$vec);83         my $result=($n*&sum(\@power))/(($n-1)*($n-2)*&sd($vec)*&sd($vec)*&sd($vec));84         return $result;85         }86 }87 88 #求峰度系数89 my @ex7=(1,9,4,9,10,12);90 print &kurt(\@ex7),"\n";91 sub kurt{92     my($vec)=@_;93     my $m=&mean($vec);94     my $n=scalar @$vec;95     my @power=map(($_-$m)*($_-$m)*($_-$m)*($_-$m),@$vec);96     my $result=&sum(\@power)/(($n-1)*&sd($vec)*&sd($vec)*&sd($vec)*&sd($vec));97     return $result;98 }