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《Perl 5教程》及《perl常问问题集》

<LI>
<A HREF="perlfaq3.html#_b_i_H_Perl_V_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq3.html#_b_i_H_Perl_V_">在哪可以学到用
Perl作物件导向程式设计?</A></LI>

<LI>
<A HREF="perlfaq3.html#_i_H_N_C_P_Perl_s_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq3.html#_i_H_N_C_P_Perl_s_">哪里可以学到将
C与 Perl相连结? [h2xs, xsubpp]</A></LI>

<LI>
<A HREF="perlfaq3.html#_w_g_F_perlembed_perlguts_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq3.html#_w_g_F_perlembed_perlguts_">我已经读了
perlembed, perlguts,等等，但我仍然无法将 perl嵌入我的</A></LI>

<LI>
<A HREF="perlfaq3.html#_A_Y" tppabs="http://202.96.217.5/~xiaoyi/perlfaq3.html#_A_Y">当我试着执行我的程式时，我收到某项讯息。它代表什麽意思?</A></LI>

<LI>
<A HREF="perlfaq3.html#_O_MakeMaker_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq3.html#_O_MakeMaker_">什麽是
MakeMaker?</A></LI>
</UL>

<LI>
<A HREF="perlfaq3.html#_P_v_y" tppabs="http://202.96.217.5/~xiaoyi/perlfaq3.html#_P_v_y">作者与版权事宜</A></LI>
</UL>

<H3>
perlfaq4</H3>

<UL>
<LI>
<A HREF="perlfaq4.html#NAME" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#NAME">NAME</A></LI>

<LI>
<A HREF="perlfaq4.html#DESCRIPTION" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#DESCRIPTION">DESCRIPTION</A></LI>

<LI>
<A HREF="perlfaq4.html#Data_Numbers" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#Data_Numbers">Data:
Numbers</A></LI>

<UL>
<LI>
<A HREF="perlfaq4.html#Why_am_I_getting_long_decimals_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#Why_am_I_getting_long_decimals_">Why
am I getting long decimals (eg, 19.9499999999999) instead of the numbers
I should be getting (eg, 19.95)?</A></LI>

<LI>
<A HREF="perlfaq4.html#Why_isn_t_my_octal_data_interpre" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#Why_isn_t_my_octal_data_interpre">Why
isn't my octal data interpreted correctly?</A></LI>

<LI>
<A HREF="perlfaq4.html#Does_perl_have_a_round_function_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#Does_perl_have_a_round_function_">Does
perl have a round function? What about ceil() and floor()?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_convert_bits_into_ints_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_convert_bits_into_ints_">How
do I convert bits into ints?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_multiply_matrices_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_multiply_matrices_">How
do I multiply matrices?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_perform_an_operation_on" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_perform_an_operation_on">How
do I perform an operation on a series of integers?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_can_I_output_Roman_numerals_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_can_I_output_Roman_numerals_">How
can I output Roman numerals?</A></LI>

<LI>
<A HREF="perlfaq4.html#Why_aren_t_my_random_numbers_ran" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#Why_aren_t_my_random_numbers_ran">Why
aren't my random numbers random?</A></LI>
</UL>

<LI>
<A HREF="perlfaq4.html#Data_Dates" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#Data_Dates">Data:
Dates</A></LI>

<UL>
<LI>
<A HREF="perlfaq4.html#How_do_I_find_the_week_of_the_ye" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_find_the_week_of_the_ye">How
do I find the week-of-the-year/day-of-the-year?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_can_I_compare_two_date_strin" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_can_I_compare_two_date_strin">How
can I compare two date strings?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_can_I_take_a_string_and_turn" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_can_I_take_a_string_and_turn">How
can I take a string and turn it into epoch seconds?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_can_I_find_the_Julian_Day_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_can_I_find_the_Julian_Day_">How
can I find the Julian Day?</A></LI>

<LI>
<A HREF="perlfaq4.html#Does_Perl_have_a_year_2000_probl" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#Does_Perl_have_a_year_2000_probl">Does
Perl have a year 2000 problem?</A></LI>
</UL>

<LI>
<A HREF="perlfaq4.html#Data_Strings" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#Data_Strings">Data:
Strings</A></LI>

<UL>
<LI>
<A HREF="perlfaq4.html#How_do_I_validate_input_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_validate_input_">How
do I validate input?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_unescape_a_string_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_unescape_a_string_">How
do I unescape a string?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_remove_consecutive_pair" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_remove_consecutive_pair">How
do I remove consecutive pairs of characters?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_expand_function_calls_i" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_expand_function_calls_i">How
do I expand function calls in a string?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_find_matching_nesting_a" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_find_matching_nesting_a">How
do I find matching/nesting anything?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_reverse_a_string_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_reverse_a_string_">How
do I reverse a string?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_expand_tabs_in_a_string" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_expand_tabs_in_a_string">How
do I expand tabs in a string?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_reformat_a_paragraph_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_reformat_a_paragraph_">How
do I reformat a paragraph?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_can_I_access_change_the_firs" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_can_I_access_change_the_firs">How
can I access/change the first N letters of a string?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_change_the_Nth_occurren" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_change_the_Nth_occurren">How
do I change the Nth occurrence of something?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_can_I_count_the_number_of_oc" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_can_I_count_the_number_of_oc">How
can I count the number of occurrences of a substring within a string?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_capitalize_all_the_word" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_capitalize_all_the_word">How
do I capitalize all the words on one line?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_can_I_split_a_character_de" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_can_I_split_a_character_de">How
can I split a [character] delimited string except when inside [character]?
(Comma-separated files)</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_strip_blank_space_from_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_strip_blank_space_from_">How
do I strip blank space from the beginning/end of a string?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_extract_selected_column" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_extract_selected_column">How
do I extract selected columns from a string?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_find_the_soundex_value_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_find_the_soundex_value_">How
do I find the soundex value of a string?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_can_I_expand_variables_in_te" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_can_I_expand_variables_in_te">How
can I expand variables in text strings?</A></LI>

<LI>
<A HREF="perlfaq4.html#What_s_wrong_with_always_quoting" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#What_s_wrong_with_always_quoting">What's
wrong with always quoting "$vars"?</A></LI>

<LI>
<A HREF="perlfaq4.html#Why_don_t_my_HERE_documents_wo" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#Why_don_t_my_HERE_documents_wo">Why
don't my &lt;<HERE documents work?</A></A></LI>
</UL>

<LI>
<A HREF="perlfaq4.html#Data_Arrays" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#Data_Arrays">Data:
Arrays</A></LI>

<UL>
<LI>
<A HREF="perlfaq4.html#What_is_the_difference_between_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#What_is_the_difference_between_">What
is the difference between $array[1] and @array[1]?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_can_I_extract_just_the_uniqu" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_can_I_extract_just_the_uniqu">How
can I extract just the unique elements of an array?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_can_I_tell_whether_an_array_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_can_I_tell_whether_an_array_">How
can I tell whether an array contains a certain element?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_compute_the_difference_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_compute_the_difference_">How
do I compute the difference of two arrays? How do I compute the intersection
of two arrays?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_find_the_first_array_el" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_find_the_first_array_el">How
do I find the first array element for which a condition is true?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_handle_linked_lists_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_handle_linked_lists_">How
do I handle linked lists?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_handle_circular_lists_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_handle_circular_lists_">How
do I handle circular lists?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_shuffle_an_array_random" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_shuffle_an_array_random">How
do I shuffle an array randomly?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_process_modify_each_ele" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_process_modify_each_ele">How
do I process/modify each element of an array?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_select_a_random_element" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_select_a_random_element">How
do I select a random element from an array?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_permute_N_elements_of_a" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_permute_N_elements_of_a">How
do I permute N elements of a list?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_sort_an_array_by_anyth" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_sort_an_array_by_anyth">How
do I sort an array by (anything)?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_manipulate_arrays_of_bi" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_manipulate_arrays_of_bi">How
do I manipulate arrays of bits?</A></LI>

<LI>
<A HREF="perlfaq4.html#Why_does_defined_return_true_o" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#Why_does_defined_return_true_o">Why
does defined() return true on empty arrays and hashes?</A></LI>
</UL>

<LI>
<A HREF="perlfaq4.html#Data_Hashes_Associative_Arrays" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#Data_Hashes_Associative_Arrays">Data:
Hashes (Associative Arrays)</A></LI>

<UL>
<LI>
<A HREF="perlfaq4.html#How_do_I_process_an_entire_hash_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_process_an_entire_hash_">How
do I process an entire hash?</A></LI>

<LI>
<A HREF="perlfaq4.html#What_happens_if_I_add_or_remove_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#What_happens_if_I_add_or_remove_">What
happens if I add or remove keys from a hash while iterating over it?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_look_up_a_hash_element_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_look_up_a_hash_element_">How
do I look up a hash element by value?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_can_I_know_how_many_entries_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_can_I_know_how_many_entries_">How
can I know how many entries are in a hash?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_sort_a_hash_optionally" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_sort_a_hash_optionally">How
do I sort a hash (optionally by value instead of key)?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_can_I_always_keep_my_hash_so" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_can_I_always_keep_my_hash_so">How
can I always keep my hash sorted?</A></LI>

<LI>
<A HREF="perlfaq4.html#What_s_the_difference_between_d" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#What_s_the_difference_between_d">What's
the difference between "delete" and "undef" with hashes?</A></LI>

<LI>
<A HREF="perlfaq4.html#Why_don_t_my_tied_hashes_make_th" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#Why_don_t_my_tied_hashes_make_th">Why
don't my tied hashes make the defined/exists distinction?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_reset_an_each_operati" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_reset_an_each_operati">How
do I reset an each() operation part-way through?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_can_I_get_the_unique_keys_fr" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_can_I_get_the_unique_keys_fr">How
can I get the unique keys from two hashes?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_can_I_store_a_multidimension" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_can_I_store_a_multidimension">How
can I store a multidimensional array in a DBM file?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_can_I_make_my_hash_remember_" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_can_I_make_my_hash_remember_">How
can I make my hash remember the order I put elements into it?</A></LI>

<LI>
<A HREF="perlfaq4.html#Why_does_passing_a_subroutine_an" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#Why_does_passing_a_subroutine_an">Why
does passing a subroutine an undefined element in a hash create it?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_can_I_make_the_Perl_equivale" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_can_I_make_the_Perl_equivale">How
can I make the Perl equivalent of a C structure/C++ class/hash or array
of hashes or arrays?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_can_I_use_a_reference_as_a_h" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_can_I_use_a_reference_as_a_h">How
can I use a reference as a hash key?</A></LI>
</UL>

<LI>
<A HREF="perlfaq4.html#Data_Misc" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#Data_Misc">Data:
Misc</A></LI>

<UL>
<LI>
<A HREF="perlfaq4.html#How_do_I_handle_binary_data_corr" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_handle_binary_data_corr">How
do I handle binary data correctly?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_determine_whether_a_sca" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_determine_whether_a_sca">How
do I determine whether a scalar is a number/whole/integer/float?</A></LI>

<LI>
<A HREF="perlfaq4.html#How_do_I_keep_persistent_data_ac" tppabs="http://202.96.217.5/~xiaoyi/perlfaq4.html#How_do_I_keep_persistent_data_ac">How
do I keep persistent data across program calls?</A></LI>