我现在正在学习perl并且有一个简短的脚本,我在其中访问一个数据库(DBI模块)来提取一些统计信息 . 下面发布的代码似乎有点重复,我想知道它是否可以简化为哈希循环 . 每个数据库查询的唯一区别是myo_maps_study中的正则表达式
#Get the number of myo stress studies
$sth = $dbh->prepare("SELECT count(myo_maps_study) FROM myo WHERE myo_maps_study ~ 'MYO[0-9]*\$' AND myo_date <= ? AND myo_date >= ?");
$sth->execute($date_stop,$date_start) or die "Couldn't execute myo stress query" . $sth->errstr;
my $n_myo_stress = $sth->fetchrow_array;
#Get the number of myo redistribution studies
$sth = $dbh->prepare("SELECT count(myo_maps_study) FROM myo WHERE myo_maps_study ~ 'MYO[0-9]*R\$' AND myo_date <= ? AND myo_date >= ?");
$sth->execute($date_stop,$date_start) or die "Couldn't execute myo rep query" . $sth->errstr;
my $n_myo_rep = $sth->fetchrow_array;
#Stress tomos
$sth = $dbh->prepare("SELECT count(myo_maps_study) FROM myo WHERE myo_maps_study ~ 'MYO[0-9]*T\$' AND myo_date <= ? AND myo_date >= ?");
$sth->execute($date_stop,$date_start) or die "Couldn't execute myo stress tomo query" . $sth->errstr;
my $n_stress_tomo = $sth->fetchrow_array;
#Rest tomos
$sth = $dbh->prepare("SELECT count(myo_maps_study) FROM myo WHERE myo_maps_study ~ 'MYO[0-9]*U\$' AND myo_date <= ? AND myo_date >= ?");
$sth->execute($date_stop,$date_start) or die "Couldn't execute myo rest tomo query" . $sth->errstr;
my $n_rest_tomo = $sth->fetchrow_array;
print "***** Imaging Statistics ************\n";
print "n_myo_stress: $n_myo_stress \n";
print "n_myo_rep: $n_myo_rep \n";
print "n_stress_tomo: $n_stress_tomo \n";
print "n_rest_tomo: $n_rest_tomo \n";
print "\n\n***********************************\n";
例如,我可以创建一个哈希数组,其中键值为n_myo_stress,n_myo_rep等,它们的值是正则表达式MYO [0-9] \ $,MYO [0-9] * R \ $等
然后,我可以使用 $sth->execute(hash value, $date_stop, $date_start)
执行我的数据库查询,并将查询结果分配给形式为$ hash_key的标量(即$ n_myo_stress) . 最后将结果打印到终端
我为糟糕的格式和缩进道歉,我不确定如何在堆栈溢出时执行此操作
1 回答
你不需要哈希,你可以这样做: