基础示例2:使用正则表达式修改文本描述:Perl和其他许多语言提供的一个正则表达式特性:替换(substiution或者叫做查找和替换(search and replace)) 代码语言:javascript 代码运行次数:0 运行 AI代码解释 #!/bin/perl #替换修改文本 #示例1 $string = "this is a demo"; $string =~ s/is/
my $variable = "world"; my $string = "Hello, Perl!"; $string =~ s/Perl/$variable/; print $string; 在这个示例中,我们将$variable的值设置为"world",并将$string的值设置为"Hello, Perl!"。然后,我们使用s/Perl/$variable/运算符将"Perl"替换为$variable的值,即"world"。最后,我们打印出替换...
我建議你最好在每個副程式前面加上對這段副程式的描述,特別是需要傳遞的參數要註明清楚。 (d) Variable Localization:my or local通常我們在程式中定義的變數都是全域變數,所以在副程式中若要把變數區域化則要加上 my 或 local 關鍵字,例如:my $x=3;,若副程式所用的變數名不小心和主程相同,Perl會以目前正在...
When an array or slice is interpolated into a double-quoted string, this variable specifies the string to put between individual elements. Default is space. O(O(OSNAME) 存储平台名 !(!(ERRNO, $OS_ERROR) 数值上下文:最近一次调用的返回值 字符串上下文:响应系统错误信息 ,(,(OFS, $OUTPUT_FIE...
Change the connection to the Sybase DBI and SQL Server DSN. The script in Step 4 has been rewritten to use DBD::Sybase. Note that the changes have been made in the header for the DBD and in the connection string for SQL Server. The rest of the Perl code is untouched by this change...
quotemetais useful when doing literal string replacements. substitute.pl #!/usr/bin/perl use strict; use warnings; use v5.34.0; my $search = 'price: $100'; my $replace = 'cost: €85'; my $text = 'The price: $100 was reduced from price: $150'; ...
Running Perl programs Safety net Basic syntax overview Perl variable types Scalars, Arrays, Hashes Variable scoping Conditional and looping constructs if, while, for, foreach Builtin operators and functions Arithmetic, Numeric comparison, String comparison, Boolean logic, Miscellaneous Files and I/O ...
eval STRING Any errors are returned in the @a variable. index This function returns the position of the first occurance of the specified SEARCH string. If POSITION is specified, the occurance at or after the position is returned. The value -1 is returned if the SEARCH string is not found....
Perl 诊断消息 类别含义 (W)警告(可选) (D)反对(可选) (S)严重警告(必需) (F)致命错误(可捕获) (P)你应该从未见过的内部错误(恐慌性的)(可捕获) (X)非常致命的错误(不可捕获) (A)外来错误消息(不是Perl生成的)
a number (Perl does not distinguish between an integer and a float) a string a reference to any other variable. my$undef=undef;print$undef;# prints the empty string "" and raises a warning# implicit undef:my$undef2;print$undef2;# prints "" and raises exactly the same warning ...