laravel PHP Carbon 类更改了我的原始变量值
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PHP Carbon class changing my original variable value
提问by Johan Bj?rklund
I'm trying to make a few navigation buttons in a calendar type thing I'm creating, and I'm using carbon to create the dates.
我正在尝试在我正在创建的日历类型的东西中制作一些导航按钮，并且我正在使用 carbon 来创建日期。
This is the code in the controller:
这是控制器中的代码：
if ($date == null) {
$date = \Carbon\Carbon::now();
} else {
$date = \Carbon\Carbon::createFromFormat('Y-m-d', $date);
}
$navDays = [
'-7Days' => $date->subDay('7')->toDateString(),
'-1Day' => $date->subDay('1')->toDateString(),
'Today' => $date->today()->toDateString(),
'+1Day' => $date->addDay('1')->toDateString(),
'+7Days' => $date->addDay('7')->toDateString()
];
and then I'm my view, I'm doing this:
然后我是我的观点，我正在这样做：
@foreach($navDays as $key => $i)
<li>
<a href="/planner/bookings/{{ $i }}" class="small button">
{{ $key }}
</a>
</li>
@endforeach
This problem is, that carbon seems to change the $date during the array creating, because these are the dates I'm getting(with $datebeing set to 2015-11-29):
这个问题是，carbon 似乎在数组创建期间更改了 $date，因为这些是我正在获取的日期（$date设置为2015-11-29）：
<ul class="button-group even-5">
<li><a href="/planner/bookings/2015-11-22" class="small button">-7Days</a></li>
<li><a href="/planner/bookings/2015-11-21" class="small button">-1Day</a></li>
<li><a href="/planner/bookings/2015-12-22" class="small button">Today</a></li>
<li><a href="/planner/bookings/2015-11-22" class="small button">+1Day</a></li>
<li><a href="/planner/bookings/2015-11-29" class="small button">+7Days</a></li>
</ul>
Does anybody know what I'm doing wrong?
有谁知道我做错了什么？
回答by diggersworld
When you run these methods against a Carbon object it updates the object itself. Therefore addDay()moves the value of Carbon one day forward.
当您针对 Carbon 对象运行这些方法时，它会更新对象本身。因此，addDay()将 Carbon 的价值向前移动一天。
Here's what you need to do:
您需要执行以下操作：
$now = Carbon::now();
$now->copy()->addDay();
$now->copy()->addMonth();
$now->copy()->addYear();
// etc...
The copy method essentially creates a new Carbon object which you can then apply the changes to without affecting the original $nowvariable.
copy 方法本质上创建了一个新的 Carbon 对象，然后您可以将更改应用于该对象，而不会影响原始$now变量。
To sum up, the methods for copying a Carbon instance are:
总结一下，复制一个Carbon实例的方法有：
copyclone- an alias ofcopy
copyclone- 别名copy
Check out the documentation: https://carbon.nesbot.com/docs/
回答by Mark Baker
The problem is that you're assuming that subDay()/addDay() don't change the date object, whereas they do.... they're just wrapping around the DateTimeobject modify()method:
问题是您假设 subDay()/addDay() 不会更改日期对象，而它们会更改....它们只是围绕DateTime对象modify()方法进行包装：
DateTime::modify -- date_modify — Altersthe timestamp
DateTime::modify -- date_modify --改变时间戳
(my emphasis)
（我的重点）
Instead, use
相反，使用
$navDays = [
'-7Days' => (clone $date)->subDay('7')->toDateString(),
'-1Day' => (clone $date)->subDay('1')->toDateString(),
'Today' => (clone $date)->today()->toDateString(),
'+1Day' => (clone $date)->addDay('1')->toDateString(),
'+7Days' => (clone $date)->addDay('7')->toDateString()
];
回答by Yevgeniy Afanasyev
Docosays
多科说
You can also create a copy() of an existing Carbon instance. As expected the date, time and timezone values are all copied to the new instance.
您还可以创建现有 Carbon 实例的 copy() 。正如预期的那样，日期、时间和时区值都被复制到新实例中。
$dt = Carbon::now();
echo $dt->diffInYears($dt->copy()->addYear()); // 1
// $dt was unchanged and still holds the value of Carbon:now()
