我有一些perl代码，我写这些代码是为了从NOAA获取天气数据/警报。
我的代码非常简单：
use Weather::NOAA::Alert;
use Data::Dumper;
$alert = Weather::NOAA::Alert->new(['TXC301']);
$events = $alert->get_events();
$alert->poll_events();
print Dumper($events);
# @url = (keys %{$VAR1->{'TXC301'}});
# $url = $VAR1->{'TXC301'};
$url = $events->{'TXC301'};
print "URL is $url\n";
# $expires= $events->{'TXC301'}->{$url}->{'expires'};
$expires= $events->{'TXC301'}->{'http://alerts.weather.gov/cap/wwacapget.php?x=TX12516CBE9400.FloodWarning.12516CC068C0TX.MAFFLWMAF.f21e7ce7cf8e930ab73a110c4d912576'}->{'expires'};
print "Expires: $expires\n";
输出：
$VAR1 = {
'TXC301' => {
'http://alerts.weather.gov/cap/wwacapget.php?x=TX12516CBE9400.FloodWarning.12516CC068C0TX.MAFFLWMAF.f21e7ce7cf8e930ab73a110c4d912576' => {
'certainty' => 'Likely',
'senderName' => 'NWS Midland-Odessa (Western Texas and Southeastern New Mexico)',
'urgency' => 'Expected',
'instruction' => 'A FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR HAS BEEN REPORTED.
STREAM RISES WILL BE SLOW AND FLASH FLOODING IS NOT EXPECTED.
HOWEVER... ALL INTERESTED PARTIES SHOULD TAKE NECESSARY PRECAUTIONS
IMMEDIATELY.
DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.',
'description' => 'THE NATIONAL WEATHER SERVICE IN MIDLAND HAS ISSUED A
FLOOD WARNING FOR...
SOUTHWESTERN LOVING COUNTY IN WEST TEXAS...
NORTHWESTERN WARD COUNTY IN WEST TEXAS...
NORTH CENTRAL REEVES COUNTY IN SOUTHWEST TEXAS...
UNTIL 300 PM CDT FRIDAY
AT 259 AM CDT...ROADS REMAIN CLOSED NEAR THE PECOS RIVER BETWEEN
RED BLUFF AND INTERSTATE 20 BECAUSE OF ELEVATED RIVER LEVELS DUE
TO RECENT RAINS. FLOODING WILL ALSO IMPACT THE CITY OF PECOS.',
'event' => 'Flood Warning',
'delete' => 0,
'category' => 'Met',
'severity' => 'Moderate',
'effective' => '2014-09-26T03:00:00-05:00',
'headline' => 'Flood Warning issued September 26 at 3:00AM CDT until September 26 at 3:00PM CDT by NWS Midland-Odessa',
'expires' => '2014-09-26T15:00:00-05:00'
}
}
};
URL is HASH(0x26384c0)
Expires: 2014-09-26T15:00:00-05:00
TXC301是报告标识符。
脚本的输出将打印从NOAA获取的所有值。
目标是存储/返回'过期'值。
我已经注释掉了一些线条，这些线条是为了实现我的目标。
我遇到的问题是获取$ url变量。我需要此值才能获得$ expires值。我的代码中的第二行到最后一行将正确获取$ expires值，但为了做到这一点，我需要将URL硬编码到行中。
我正试图让直线上方（从第3位到最后位）上线：
$expires= $events->{'TXC301'}->{$url}->{'expires'};
但这取决于要存储的$ url值。 我似乎无法弄清楚如何获得$ url值。
我的猜测：
@url = (keys %{$VAR1->{'TXC301'}});
$url = $VAR1->{'TXC301'};
$url = $events->{'TXC301'};
这些都不起作用。
任何帮助都会很棒。
谢谢！
此致
Joseph Spenner
答案 0 :(得分：2)
鉴于该级别的散列引用只有一个值，您可以使用values：
print +( values %{ $VAR1->{TXC301} } )[0]{expires}, "\n";
输出：
2014-09-26T15:00:00-05:00
此外，在另一个问题上，我建议在核心库Data::Dump上使用Data::Dumper。
此备选方案的默认设置和功能可提供出色的输出，并使人们可以更快地分析数据结构，如下所示：
$VAR1 = {
'TXC301' => {
'http://alerts.weather.gov/cap/wwacapget.php?x=TX12516CBE9400.FloodWarning.12516CC068C0TX.MAFFLWMAF.f21e7ce7cf8e930ab73a110c4d912576' => {
'certainty' => 'Likely',
'senderName' => 'NWS Midland-Odessa (Western Texas and Southeastern New Mexico)',
'urgency' => 'Expected',
'instruction' => 'A FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR HAS BEEN REPORTED.
STREAM RISES WILL BE SLOW AND FLASH FLOODING IS NOT EXPECTED.
HOWEVER... ALL INTERESTED PARTIES SHOULD TAKE NECESSARY PRECAUTIONS
IMMEDIATELY.
DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.',
'description' => 'THE NATIONAL WEATHER SERVICE IN MIDLAND HAS ISSUED A
FLOOD WARNING FOR...
SOUTHWESTERN LOVING COUNTY IN WEST TEXAS...
NORTHWESTERN WARD COUNTY IN WEST TEXAS...
NORTH CENTRAL REEVES COUNTY IN SOUTHWEST TEXAS...
UNTIL 300 PM CDT FRIDAY
AT 259 AM CDT...ROADS REMAIN CLOSED NEAR THE PECOS RIVER BETWEEN
RED BLUFF AND INTERSTATE 20 BECAUSE OF ELEVATED RIVER LEVELS DUE
TO RECENT RAINS. FLOODING WILL ALSO IMPACT THE CITY OF PECOS.',
'event' => 'Flood Warning',
'delete' => 0,
'category' => 'Met',
'severity' => 'Moderate',
'effective' => '2014-09-26T03:00:00-05:00',
'headline' => 'Flood Warning issued September 26 at 3:00AM CDT until September 26 at 3:00PM CDT by NWS Midland-Odessa',
'expires' => '2014-09-26T15:00:00-05:00'
}
}
};
use Data::Dump;
dd $VAR1;
输出：
{
TXC301 => {
"http://alerts.weather.gov/cap/wwacapget.php?x=TX12516CBE9400.FloodWarning.12516CC068C0TX.MAFFLWMAF.f21e7ce7cf8e930ab73a110c4d912576" => {
category => "Met",
certainty => "Likely",
delete => 0,
description => "THE NATIONAL WEATHER SERVICE IN MIDLAND HAS ISSUED A\n FLOOD WARNING FOR...\nSOUTHWESTERN LOVING COUNTY IN WEST TEXAS...\nNORTHWESTERN WARD COUNTY IN WEST TEXAS...\nNORTH CENTRAL REEVES COUNTY IN SOUTHWEST TEXAS...\n UNTIL 300 PM CDT FRIDAY\n AT 259 AM CDT...ROADS REMAIN CLOSED NEAR THE PECOS RIVER BETWEEN\nRED BLUFF AND INTERSTATE 20 BECAUSE OF ELEVATED RIVER LEVELS DUE\nTO RECENT RAINS. FLOODING WILL ALSO IMPACT THE CITY OF PECOS.",
effective => "2014-09-26T03:00:00-05:00",
event => "Flood Warning",
expires => "2014-09-26T15:00:00-05:00",
headline => "Flood Warning issued September 26 at 3:00AM CDT until September 26 at 3:00PM CDT by NWS Midland-Odessa",
instruction => "A FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR HAS BEEN REPORTED.\nSTREAM RISES WILL BE SLOW AND FLASH FLOODING IS NOT EXPECTED.\nHOWEVER... ALL INTERESTED PARTIES SHOULD TAKE NECESSARY PRECAUTIONS\nIMMEDIATELY.\nDO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE\nROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS\nSAFELY.",
senderName => "NWS Midland-Odessa (Western Texas and Southeastern New Mexico)",
severity => "Moderate",
urgency => "Expected",
},
},
}
答案 1 :(得分：1)
my @url = values %{ $VAR1->{'TXC301'} };
print $_->{expires}, "\n" for @url;
答案 2 :(得分：0)
好的，我能够把一些有用的东西拼凑起来：
use Weather::NOAA::Alert;
use Data::Dumper;
$alert = Weather::NOAA::Alert->new(['TXC301']);
$events = $alert->get_events();
$alert->poll_events();
Dumper($events);
print +( values %{ $events->{TXC301} } )[0]{expires}, "\n";
通过在最后一行中将$VAR1更改为$events，我摆脱了错误并获得了我需要的确切输出。
感谢所有快速回复！
此致 Joseph Spenner