本文介绍了如何删除 Perl 字符串中的空格?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
如果我声明了一个变量 $myString，其值为 '3'(注意空格).是否有任何函数可以删除返回值的空格.有点像 SomeFun($myString) 然后返回 '3' (没有空格).
If I declared a variable $myString with the value '3 ' (notice the white space).Is there any function to remove the white space for the return value.A little like SomeFun($myString) then return '3' (without white space).
#!C:\Perl\bin\perl.exe
use strict;
use warnings;
use Data::Dumper;
my $fh = \*DATA;
print Dumper parse_constant_spec( $fh );
# Parse a constant spec file.
# Pass in a handle to process.
# As long as it acts like a file handle, it will work.
sub parse_constant_spec {
my $fh = shift;
my %spec;
# Until file is done:
# Read in a whole block
while( my $block = read_block($fh) ) {
# Parse the and return key/value pairs for a hash.
my %constant = parse_block( $block );
# Store a ref to the hash in a big hash of all blocks, keyed by constant_name.
$spec{ $constant{const_name} } = \%constant;
}
# Return ref to big hash with all block data
return \%spec;
}
# Read a constant definition block from a file handle.
# void return when there is no data left in the file.
# Otherwise return an array ref containing lines to in the block.
sub read_block {
my $fh = shift;
my @lines;
my $block_started = 0;
while( my $line = <$fh> ) {
$block_started++ if $line =~ /^constant/;
if( $block_started ) {
last if $line =~ /^\s*$/;
push @lines, $line;
}
}
return \@lines if @lines;
return;
}
sub parse_block {
my $block = shift;
my ($start_line, @attribs) = @$block;
my %constant;
# Break down first line:
# First separate assignment from option list.
my ($start_head, $start_tail) = split /=/, $start_line;
# work on option list
my @options = split /\s+/, $start_head;
# Recover constant_name from options:
$constant{const_name} = pop @options;
$constant{options} = \@options;
# Now we parse the value/type specifier
@constant{'type', 'value' } = parse_type_value_specifier( $start_tail );
# Parse attribute lines.
# since we've already got multiple per line, get them all at once.
chomp @attribs;
my $attribs = join ' ', @attribs;
# we have one long line of mixed key = "value" or key = <TYPE VALUE>
@attribs = $attribs =~ /\s*(\w+\s+=\s+\w+\s+|\w+\s+=\s+".*?"|\w+\s+=\s+<.*?>)\s*/g;
for my $attrib ( @attribs ) {
warn "$attrib\n";
my ($name, $value) = split /\s*=\s*/, $attrib;
if( $value =~ /^"/ ) {
$value =~ s/^"|"\s*$//g;
}
elsif( $value =~ /^</ ) {
$value = [ parse_type_value_specifier( $start_tail ) ];
}
else {
warn "Bad line";
}
$constant{ $name } = $value;
}
return %constant;
}
sub parse_type_value_specifier {
my $tvs = shift;
my ($type, $value) = $tvs =~ /<(\w+)\s+(.*?)>/;
return $type, $value;
}
__DATA__
constant fixup GemEstabCommDelay = <U2 20>
vid = 6
name = "ESTABLISHCOMMUNICATIONSTIMEOUT"
units = "s"
min = <U2 0>
max = <U2 1800>
default = <U2 20>
constant fixup private GemConstantFileName = <A "C:\\TMP\\CONST.LOG">
vid = 4
name = "" units = ""
constant fixup private GemAlarmFileName = <A "C:\\TMP\\ALARM.LOG">
vid = 0
name = ""
units = ""
输出:
D:\learning\perl>hello1.pl
vid = 6
Bad line at D:\learning\perl\hello1.pl line 102, <DATA> line 8.
name = "ESTABLISHCOMMUNICATIONSTIMEOUT"
units = "s"
min = <U2 0>
max = <U2 1800>
default = <U2 20>
vid = 4
Bad line at D:\learning\perl\hello1.pl line 102, <DATA> line 13.
name = ""
units = ""
vid = 0
Bad line at D:\learning\perl\hello1.pl line 102, <DATA> line 18.
name = ""
units = ""
$VAR1 = {
'GemAlarmFileName' => {
'vid' => '0 ',
'options' => [
'constant',
'fixup',
'private'
],
'value' => '"C:\\\\TMP\\\\ALARM.LOG"',
'name' => '',
'type' => 'A',
'const_name' => 'GemAlarmFileName',
'units' => ''
},
'GemEstabCommDelay' => {
'vid' => '6 ',
'options' => [
'constant',
'fixup'
],
'value' => '20',
'min' => [
'U2',
'20'
],
'name' => 'ESTABLISHCOMMUNICATIONSTIMEOUT',
'max' => [
'U2',
'20'
],
'default' => [
'U2',
'20'
],
'type' => 'U2',
'units' => 's',
'const_name' => 'GemEstabCommDelay'
},
'GemConstantFileName' => {
'vid' => '4 ',
'options' => [
'constant',
'fixup',
'private'
],
'value' => '"C:\\\\TMP\\\\CONST.LOG"',
'name' => '',
'type' => 'A',
'const_name' => 'GemConstantFileName',
'units' => ''
}
};
D:\learning\perl>
你会注意到 'vid' =>'0',(注意空格)
You could notice that 'vid' => '0 ', (notice the white space)
以上代码来自答案.我正在研究它.:-)
The code above from the answer. I am studying it. :-)
谢谢.
推荐答案
$myString =~ s/^\s*(.*?)\s*$/$1/;
这将修剪两边的空白.
从右边:
$myString =~ s/\s*$//;
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