perl的array和map/hash
发布时间：2020-12-16 00:16:40 所属栏目：大数据 来源：网络整理
导读：? 一 array 1）实例 use ?strict; use ?warnings; my ? @myarray ? = ?( 123 , " hello " , ? 456 , ? ' guy ' ); foreach ( @myarray ) { ???? print ? " $_? " ?; } print ? " n " ; foreach ? my ? $item ?( @myarray ) { ???? print ? " $item? " ?; }
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? 一 array 1）实例 use ?strict; use ?warnings; my ? @myarray ? = ?( 123 , " hello " , ? 456 , ? ' guy ' ); foreach ( @myarray ) { ???? print ? " $_? " ?; } print ? " n " ; foreach ? my ? $item ?( @myarray ) { ???? print ? " $item? " ?; } print ? " n " ; for ( my ? $i ? = ? 0 ;? $i ? < scalar ( @myarray );? $i ++ ) { ???? print ? " $myarray[$i] " ? . ? " ? " ; } print ? " n " ; for ( 0 .. ($ # myarray)) { ???? print ? " $myarray[$_] " ? . ? " ? " ; } print ? " n " ; @myarray ? = ?( @myarray , ? 789 ); print ? " @myarrayn " ?; push ( @myarray , " gril " ); print ? " @myarrayn " ?; unshift ( @myarray , ? ' 000 ' ); print ? " @myarrayn " ?;
delete $myarray[1];
print "@myarrayn" ; ? 2）函数，如下：
3）注释： 1】使用@定义array，使用array的item时$array[n]； 2】使用scalar来获得array的size； 3】$#获得最大的index，即size-1； 4】$_在for和foreach中表示当前item； 5】push/pop用来在array的最后加入和弹出item； 6】shift/unshift用来在array的前面删除和插入item； 7】split/john用来实现array和string间的转化； 8】delete可以用来删除item，例如delete $myarray[1]; ? 二 map/hash 1) 实例： use ?strict; use ?warnings; my ? %myhash ? = ?( ' k1 ' , 100 , ' k2 ' , 200 ); # ?my?%myhash?=?(k1=>100,k2=>200); print ? %myhash ?; print ? " n " ; $myhash { ' k3 ' }? = ? 300 ; $myhash { ' k4 ' }? = ? 400 ; print ? %myhash ?; print ? " n " ; foreach ? my ? $key ?( keys ? %myhash ) { ???? print ? $key ? . ? " ?indexes? " . $myhash { $key } . " n " ; } foreach ? my ? $value ?( values ? %myhash ) { ???? print ? $value ? . " n " ; } while (( my ? $key , ? my ? $value ) = ? each ( %myhash )) { ???? print ? " $key?indexes?$value?n " } if ( exists ? $myhash { ' k1 ' })?{ print ? " k1?is?existn " ;} delete ? $myhash { ' k1 ' }; print ? %myhash ?; print ? " n " ?; ? 2）函数，如下：
3）注释： 1】%用来定义map/hash； ? 三 总
Array Functions
@array = ( ); Defines an empty array
@array = (“a”,“b”,“c”); Defines an array with values
$array[0] The first element of @array
$array[0] = a; Sets the first element of @array to a
@array[3..5] Array slice - returns a list containing the 3rd thru 5th
elements of @array
scalar(@array) Returns the number of elements in @array
$#array The index of the last element in @array
grep(/pattern/,@array) Returns a list of the items in @array that matched
/pattern/
join(expr,@array) Joins @array into a single string separated by expr
push(@array,$var) Adds $var to @array
pop(@array) Removes last element of @array and returns it
reverse(@array) Returns @array in reverse order
shift(@array) Removes first element of @array and returns it
sort(@array) Returns alphabetically sorted @array
sort({$a<=>$b},@array) Returns numerically sorted @array
?
Hash Functions
%hash = ( ); Defines an empty hash
%hash = (a => 1,b=>2); Defines a hash with values
$hash{$key} The value referred to by this $key
$hash{$key} = $value; Sets the value referred to by $key
exists $hash{$key} True if the key/value pair exists
delete $hash{$key} Deletes the key/value pair specified by $key
keys %hash Returns a list of the hash keys
values %hash Returns a list of the hash values? ? 完！ （编辑：李大同） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |
