您好，我遇到以下情况：我有一个名为getMessages()的馆藏，它具有这种结构$urls = file('urls.txt',FILE_IGNORE_NEW_LInes);
//doesn't work
echo "test:".$urls[3]."<br>";
//works fine
foreach ($urls as $url) {
echo $url."<br>";
}
和一个名为#
# Windows Service name
#
oscomponent.servicename=CA Workload Automation Agent 11.3.4
oscomponent.servicedisplayname=CA Workload Automation Agent 11.3.4
# Windows Settings
oscomponent.lookupcommand=true
oscomponent.noforceprofile=false
oscomponent.dumpenvironment=false
oscomponent.initialworkingdirectory=SCRIPT
oscomponent.cmdprefix.force=true
runnerplugin.spool.clean.enable=true
runnerplugin.spool.expire=10D
runnerplugin.spool.sleep=36H
oscomponent.joblog=true
oscomponent.cmdprefix.force=true
oscomponent.interactive=true
oscomponent.cmdprefix.force.redir.inline=true
oscomponent.interactive.session.ignoreinactive=true
oscomponent.interactive.sessionzero=true
oscomponent.logon.elevated=true
oscomponent.su.newconsole=true
oscomponent.shell=true
oscomponent.default.user=MX02689@hebmex.com
oscomponent.default.password=2390hasG
#
# Installer setting. Do not modify the setting below
#
installer.version=R11.3.4
#
# Added by Manager
#
communication.managerhealthmon_1=false
communication.socket_1=plain
的馆藏，我希望能够做一堆书通过选择将authors用作必填字段，问题是我无法实现这一目标，我想知道是否有人可以帮忙。
我正在使用angular 7和firebasecloud。
这是我为作者服务的代码
authors: {id,firstname,lastname,state}