Use of lists and arrays in Perl

Summarize some of the uses of list and array operations in Perl

Suppose you define an array variable @arr and assign the list (str_a, Str_b, Str_c, str_d) to the array @arr

@arr = (str_a, Str_b, Str_c, str_d);

Assign the number of elements in an array @arr to $var

$var = @arr;

Print this array @arr, and the elements in the array are separated by spaces

print "@arr \ n";

Prints the first and third elements and the last element of the array @arr, with the default index starting at 0 and index-1 representing the last element

print "$arr [0], $arr [2], $arr [ -1]\n];

Prints the index value of the last element of an array @arr

Print "$ #arr \ n";

Pop operator, take out the last element of the array and assign it to $var

$var = Pop @arr;

Push operator, add an element to the end of the array

Push @arr, "str_e";

Shift operator to remove the first element of the array and assign it to $var

$var = Shift @arr;

Unshift operator, add an element to the beginning of the array

Unshift @arr, "str_f";

Splice operator,

If 2 parameters are specified, the first is an array and the second is an index, then all elements after this index of the array are fetched

@brr = Splice @arr, 2;

If you specify 3 arguments, the 3rd represents the number of elements to take out, such as the element that takes the array index 1 and a total of 2 elements that follow.

@brr = Splice @arr, 1, 2;

If you specify 4 arguments, the 4th represents the replacement of the previously fetched element, for example, Str_e replaces the 2 elements that are taken out

Splice @arr, 1,2, "str_e";

List bulk Assignment, qw a list of quotes that automatically enclose

($var _a, $var _b, $var _c) = QW (Apple pear banana);

The value of a variable in an interchange list

($var _a, $var _b) = ($var _b, $var _a);

Loops Print List elements, $_ represents the default variable in the list

foreach (1..10) {

print "$_\n";

}

Reverse operator, sort the elements in the list and assign them to another array

@rra = reverse (1..10);

Sort operator that sorts the elements in the list in ASCII order

@arr = sort qw (apple pear banana);

This article is from the "Strive for" blog, please be sure to keep this source http://carllai.blog.51cto.com/1664997/1174840

See more highlights of this column: http://www.bianceng.cnhttp://www.bianceng.cn/Programming/extra/