blocks|key|1783115|text|如果你遵循SOLID原则，特别是single+responsibility+principle希望你将功能隔离到不同的功能中。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1783116|如果你真的应用了这一点，那么你实际上并没有使用相同的变量，因为在这一点上会有不同的作用域，因此这不是一个问题。|1783117|简而言之，你不应该重用变量，如果你的逻辑被分解成执行单个任务的函数，请不要将它们命名为$result1、result2等。这是code+smell在你的项目中的标志。|style|CODE|1783118|entityMap|0|LINK|mutability|MUTABLE|url|https://en.wikipedia.org/wiki/SOLID_(object-oriented_design)|1|https://en.wikipedia.org/wiki/Single_responsibility_principle|2|https://en.wikipedia.org/wiki/Code_smell^0|5|5|0|G|V|1|0|0|17|8|1G|7|1R|A|2|0^^$0|@$1|2|3|4|5|6|7|V|8|@]|9|@$A|W|B|X|1|Y]|$A|Z|B|10|1|11]]|C|$]]|$1|D|3|E|5|6|7|12|8|@]|9|@]|C|$]]|$1|F|3|G|5|6|7|13|8|@$A|14|B|15|H|I]|$A|16|B|17|H|I]]|9|@$A|18|B|19|1|1A]]|C|$]]|$1|J|3|-4|5|6|7|1B|8|@]|9|@]|C|$]]]|K|$L|$5|M|N|O|C|$P|Q]]|R|$5|M|N|O|C|$P|S]]|T|$5|M|N|O|C|$P|U]]]]

If you follow <a href="https://en.wikipedia.org/wiki/SOLID_(object-oriented_design)" rel="nofollow noreferrer">SOLID</a> principle, especially the <a href="https://en.wikipedia.org/wiki/Single_responsibility_principle" rel="nofollow noreferrer">single responsibility principle</a> wants you to isolate functionality into different function.

If you do apply this, then you are not really using the same variables, because at that point there would be in different scope, therefore it would not be an issue.

In short you shouldn't have to reuse variables, if your logic is broken up into function that perform a single task, please do not name them <code>$result1</code>, <code>result2</code> etc ... this is a sign of <a href="https://en.wikipedia.org/wiki/Code_smell" rel="nofollow noreferrer">code smell</a> in your project.

blocks|key|1488502|text|如果您已经完成了myTable1，那么它完全可以，但是如果您打算在代码中的其他地方使用它，则不可以，因为只有myTable2信息将被保存在$result中|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1488503|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

If you are done with myTable1 then it is totally ok but if you are going to use it somewhere else in code then no because only myTable2 information will be saved in $result

blocks|key|5568676|text|如果您使用相同的变量来存储数据，那么每次迭代时，变量值都会被新值覆盖，而while语句之后的值就是最后一次迭代。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|5568677|entityMap^0|10|5|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

if you use same variable to store your data then every iteration the variable value will be override with new value, and the value after <code>while</code> statement is the last iteration.

blocks|key|1493383|text|$temp是while的局部变量，如果您以前没有定义过它，那么这样使用它是安全的。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1493384|$query，从语言允许你做的事情来看，是的，你可以这样使用它。|1493385|entityMap^0|0|5|0|0|6|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|H|3|-4|5|6|7|P|8|@]|D|@]|E|$]]]|I|$]]

<code>$temp</code> is a local variable to the while if you haven't defined it before so it is safe to be used like that.

<code>$query</code>, from what the language lets you do, yes you can use it this way.

blocks|key|1493421|text|基本PHP代码|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1493422|假设您想要将数据库中的一些信息存储到变量中，然后在进行更多编码之前使用它。|1493423|所以我们有这个示例代码。将id值存储到$temp变量中。我们得到的输出是什么？|offset|length|style|CODE|1493424|$query+=+mysqli_query($db,+"SELECT+*+FROM+myTable1")

while($result+=+mysqli_fetch_assoc($query)){
+++$temp+=+$result['id'];
}|code-block|syntax|javascript|1493425|例如，表myTable1包含如下数据。|1493426|%2B----%2B---------%2B---------%2B
%7C+id+%7C++Col1+++%7C++Col2+++%7C
%2B----%2B---------%2B---------%2B
%7C++1+%7C+Value+1+%7C+Value+2+%7C
%7C++2+%7C+Value+1+%7C+Value+2+%7C
%7C++3+%7C+Value+1+%7C+Value+2+%7C
%7C++4+%7C+Value+1+%7C+Value+2+%7C
%2B----%2B---------%2B---------%2B|1493427|我们的$temp变量将等于4。因为您将从该表中获取所有内容，然后获取出现的每个结果。现在，让我们使用这个变量。|1493428|echo+'Selected+id+from+table+myTable1+equals+'+.+$temp;|1493429|这导致了|1493430|从表myTable1中选择的|1493431|+id等于4|blockquote|1493432|1493433|1493434|然后，我们从另一个名为myTable2的表中获取数据。|1493435|$query+=+mysqli_query($db,+"SELECT+*+FROM+myTable2")

while($result+=+mysqli_fetch_assoc($query)){
+++$temp+=+$result['id'];
}|1493436|该表包含这样的数据。|1493437|%2B----%2B---------%2B---------%2B
%7C+id+%7C++Col1+++%7C++Col2+++%7C
%2B----%2B---------%2B---------%2B
%7C++3+%7C+Value+1+%7C+Value+2+%7C
%7C++5+%7C+Value+1+%7C+Value+2+%7C
%7C++6+%7C+Value+1+%7C+Value+2+%7C
%7C++8+%7C+Value+1+%7C+Value+2+%7C
%2B----%2B---------%2B---------%2B|1493438|同样的事情也发生了，$temp变量现在等于8。让我们以同样的方式使用它。|1493439|echo+'Selected+id+from+table+myTable2+equals+'+.+$temp;|1493440|1493441|从表myTable2中选择的|1493442|+id等于8|1493443|1493444|1493445|最终结果|1493446|1493447|+id等于4|1493448|1493449|从表myTable2中选择的id等于8|1493450|1493451|结论|1493452|这里没什么问题。如果你愿意，你可以这么做。但请注意，如果您有更多的代码行，则不建议多次使用具有相同名称的变量。|1493453|更复杂的PHP代码|1493454|相同的表、结构和数据。让我们更改代码。|1493455|function+printIndex($id)+{
++++echo+'Index+=+'+.+$id;
}
$query+=+mysqli_query($db,+"SELECT+*+FROM+myTable1")

while($result+=+mysqli_fetch_assoc($query)){
+++$temp+=+$result['id'];+//+Store+id+for+further+use
}

$query+=+mysqli_query($db,+"SELECT+*+FROM+myTable2")

while($result+=+mysqli_fetch_assoc($query)){
+++$temp+=+$result['id'];+//+Store+id+for+further+use
}

printIndex($temp);+//+Print+stored+id|1493456|输出|1493457|1493458|索引=8|1493459|1493460|1493461|1493462|错误的编码。你必须使用唯一的变量名来防止这种情况。|1493463|entityMap^0|0|0|D|2|J|5|0|0|4|8|0|0|3|5|D|1|0|0|0|0|0|0|0|B|8|0|0|0|0|A|5|L|1|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|2J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|2K|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|2L|8|@$F|2M|G|2N|H|I]|$F|2O|G|2P|H|I]]|9|@]|A|$]]|$1|J|3|K|5|L|7|2Q|8|@]|9|@]|A|$M|N]]|$1|O|3|P|5|6|7|2R|8|@$F|2S|G|2T|H|I]]|9|@]|A|$]]|$1|Q|3|R|5|L|7|2U|8|@]|9|@]|A|$M|N]]|$1|S|3|T|5|6|7|2V|8|@$F|2W|G|2X|H|I]|$F|2Y|G|2Z|H|I]]|9|@]|A|$]]|$1|U|3|V|5|L|7|30|8|@]|9|@]|A|$M|N]]|$1|W|3|X|5|6|7|31|8|@]|9|@]|A|$]]|$1|Y|3|Z|5|6|7|32|8|@]|9|@]|A|$]]|$1|10|3|11|5|12|7|33|8|@]|9|@]|A|$]]|$1|13|3|-4|5|6|7|34|8|@]|9|@]|A|$]]|$1|14|3|-4|5|6|7|35|8|@]|9|@]|A|$]]|$1|15|3|16|5|6|7|36|8|@$F|37|G|38|H|I]]|9|@]|A|$]]|$1|17|3|18|5|L|7|39|8|@]|9|@]|A|$M|N]]|$1|19|3|1A|5|6|7|3A|8|@]|9|@]|A|$]]|$1|1B|3|1C|5|L|7|3B|8|@]|9|@]|A|$M|N]]|$1|1D|3|1E|5|6|7|3C|8|@$F|3D|G|3E|H|I]|$F|3F|G|3G|H|I]]|9|@]|A|$]]|$1|1F|3|1G|5|L|7|3H|8|@]|9|@]|A|$M|N]]|$1|1H|3|X|5|6|7|3I|8|@]|9|@]|A|$]]|$1|1I|3|1J|5|6|7|3J|8|@]|9|@]|A|$]]|$1|1K|3|1L|5|12|7|3K|8|@]|9|@]|A|$]]|$1|1M|3|-4|5|6|7|3L|8|@]|9|@]|A|$]]|$1|1N|3|-4|5|6|7|3M|8|@]|9|@]|A|$]]|$1|1O|3|1P|5|6|7|3N|8|@]|9|@]|A|$]]|$1|1Q|3|Z|5|6|7|3O|8|@]|9|@]|A|$]]|$1|1R|3|1S|5|12|7|3P|8|@]|9|@]|A|$]]|$1|1T|3|-4|5|6|7|3Q|8|@]|9|@]|A|$]]|$1|1U|3|1V|5|6|7|3R|8|@]|9|@]|A|$]]|$1|1W|3|-4|5|6|7|3S|8|@]|9|@]|A|$]]|$1|1X|3|1Y|5|6|7|3T|8|@]|9|@]|A|$]]|$1|1Z|3|20|5|6|7|3U|8|@]|9|@]|A|$]]|$1|21|3|22|5|6|7|3V|8|@]|9|@]|A|$]]|$1|23|3|24|5|6|7|3W|8|@]|9|@]|A|$]]|$1|25|3|26|5|L|7|3X|8|@]|9|@]|A|$M|N]]|$1|27|3|28|5|6|7|3Y|8|@]|9|@]|A|$]]|$1|29|3|-4|5|6|7|3Z|8|@]|9|@]|A|$]]|$1|2A|3|2B|5|12|7|40|8|@]|9|@]|A|$]]|$1|2C|3|-4|5|6|7|41|8|@]|9|@]|A|$]]|$1|2D|3|-4|5|6|7|42|8|@]|9|@]|A|$]]|$1|2E|3|1Y|5|6|7|43|8|@]|9|@]|A|$]]|$1|2F|3|2G|5|6|7|44|8|@]|9|@]|A|$]]|$1|2H|3|-4|5|6|7|45|8|@]|9|@]|A|$]]]|2I|$]]

<h1>Basic PHP code</h1>

Let's say you want to store some information from database into variable and then use it before doing some more coding.

So we have this sample code. Storing <code>id</code> value into <code>$temp</code> variable. What is the output we get?

<pre><code>$query = mysqli_query($db, "SELECT * FROM myTable1")

while($result = mysqli_fetch_assoc($query)){
 $temp = $result['id'];
}
</code></pre>

For example table <code>myTable1</code> contains data like this.

<pre><code>+----+---------+---------+
| id | Col1 | Col2 |
+----+---------+---------+
| 1 | Value 1 | Value 2 |
| 2 | Value 1 | Value 2 |
| 3 | Value 1 | Value 2 |
| 4 | Value 1 | Value 2 |
+----+---------+---------+
</code></pre>

Our <code>$temp</code> variable will be equal to <code>4</code>. Because you are getting everything from that table and then fetching every result that comes up. Now, let's use that variable.

<pre><code>echo 'Selected id from table myTable1 equals ' . $temp;
</code></pre>

Which results in

<blockquote>
 Selected id from table myTable1 equals 4
</blockquote>

Then, we are getting data from another table called <code>myTable2</code>.

<pre><code>$query = mysqli_query($db, "SELECT * FROM myTable2")

while($result = mysqli_fetch_assoc($query)){
 $temp = $result['id'];
}
</code></pre>

That table contains data like this.

<pre><code>+----+---------+---------+
| id | Col1 | Col2 |
+----+---------+---------+
| 3 | Value 1 | Value 2 |
| 5 | Value 1 | Value 2 |
| 6 | Value 1 | Value 2 |
| 8 | Value 1 | Value 2 |
+----+---------+---------+
</code></pre>

Again, same thing happens, <code>$temp</code> variable is now equal to <code>8</code>. Let's use it same way.

<pre><code>echo 'Selected id from table myTable2 equals ' . $temp;
</code></pre>

Which results in

<blockquote>
 Selected id from table myTable2 equals 8
</blockquote>

<h3>Final result</h3>

<blockquote>
 Selected id from table myTable1 equals 4 
 Selected id from table myTable2 equals 8
</blockquote>

<h3>Conclusion</h3>

Nothing wrong here. You can do that if you want. But be aware that it's not recommended to use variable with same name multiple times if you have way more lines of code.

<h1>More complex PHP code</h1>

Same tables, structure and data. Let's change code.

<pre><code>function printIndex($id) {
 echo 'Index = ' . $id;
}
$query = mysqli_query($db, "SELECT * FROM myTable1")

while($result = mysqli_fetch_assoc($query)){
 $temp = $result['id']; // Store id for further use
}

$query = mysqli_query($db, "SELECT * FROM myTable2")

while($result = mysqli_fetch_assoc($query)){
 $temp = $result['id']; // Store id for further use
}

printIndex($temp); // Print stored id
</code></pre>

<h3>Output</h3>

<blockquote>
 Index = 8
</blockquote>

<h3>Conclusion</h3>

Bad coding. You have to use unique variable names to prevent such situation.

blocks|key|1783246|text|您可以在逻辑上使用相同的变量名。它不会给你一个错误(有时，如果你在循环之外使用这些变量，在这个上下文中可能会)。但是对变量名使用通用关键字是不可取的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1783247|取而代之的是尝试根据你的模型来命名变量。请看下面的示例：|1783248|如果你的“myTable1”是关于学生的，那么你可以用$student代替$result1。同样，如果您的“myTable2”是关于产品的，那么您可以使用$product而不是$result2。|1783249|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

You can use the same variable names logically. It won't give you an error(sometimes it might if you use these variables out of your loop in this context). But using general keywords for variable names are not advisable.

Instead try to name the variables based on your Model. Please look at the below examples,

If your 'myTable1' about students then you can use $student instead of $result1. 
Again, if your 'myTable2' is about products then you can use $product instead of $result2.

I just wondering is it okay if I use the following code :

<pre><code>$query = mysqli_query($db, "SELECT * FROM myTable1")

while($result = mysqli_fetch_assoc($query)){
 $temp = $result['id'];
}
</code></pre>

Then I fetch another table like this :

<pre><code>$query = mysqli_query($db, "SELECT * FROM myTable2")

while($result = mysqli_fetch_assoc($query)){
 $temp = $result['id'];
}
</code></pre>

I use the same variable <code>$result</code> and <code>$temp</code>.
 I mean is it okay to use such code ? Should I named the variable differently like <code>$result1</code> <code>$result2</code> and so on ?
 Let's say, which one is better, safer, between use the same variable name or give the variables different name ?
 I hope someone could explain about it.
 Thank you before.

Is it okay use the same variable name on PHP while?

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没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

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我只是想知道我是否可以使用下面的代码：$query = mysqli_query($db, "SELECT * FROM myTable1")while($result = mysqli_fetch_assoc($query)){   $temp = $result['id'];}然后，我获取另一个表，如下所示：$query = mysqli_query($db, "SELECT * FROM m

问在PHP上使用相同的变量名可以吗？
EN

回答 6

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问在PHP上使用相同的变量名可以吗？EN

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问在PHP上使用相同的变量名可以吗？
EN