In PHP, what is the difference between single and double quoted strings?

I'm a little confused why in PHP some strings in the code use single quotes and some use double quotes. I just know that in .NET or C, if you use single quotes, that means it's a character, not a string.

P粉604507867 2023-08-18 11:45:01 0  2  702

What is the difference between single and double quoted strings in PHP?

I'm a little confused why I see some code in PHP where strings are put in single quotes and sometimes in double quotes. I just know that in .NET, or C, if it's in single quotes, that means it's a character, not a string.

P粉773659687 2023-08-23 20:46:33 0  2  841

Problems with nested single quotes and double quotes

The first sentence: var str = "My name is'" +name+"'"The second sentence: var str = "My name is\"" +name+"\""You said that only double quotes can be nested within single quotes. Quotes, only single quotes can be nested within double quotes. I can und...

自律者自由 2017-10-24 23:35:26 0  3  2292

The difference between single quotes and double quotes

Single quotation marks have stronger performance, but poor functionality. Double quotation marks can directly perform a simple analysis of the content of the string. For example, the performance of variables and special escape characters will be reduced accordingly. In general, single quotation mark...

P粉698851581 2022-09-22 11:01:08 0  2  2992

MySQL constrains unique index only if another column is empty

I'm trying to rewrite the Postgres schema to fit the MySQL (8.0.32) dialect. As you know, MySQL does not support partial indexes. In the following case, there will be an index that enforces unique data on customer_group.name only if deleted_at is null. This makes sense since there is no point in ens...

P粉930448030 2024-01-16 15:42:42 0  2  512

Double quotes and delimiters

The double quotes in English statements are double quotes in the English state, which are the same as the double quotes in program statements. Therefore, if there are double quotes in the (English) string within the double quotes, they will interfere with each other, so the Double quotes must be esc...

天际梦想 2019-03-03 18:53:18 0  0  1332

How to build a bilingual or multilingual website?

How to build a bilingual or multilingual website? I had some time today and took a look at ANT DESIGN PRO! I found that his method of implementing multi-language is very good and I would like to share it with you! First of all, he will have a multi-language folder, each file corresponding to a langu...

七喜 2018-11-12 12:41:30 0  1  1597

mysql: key reference and table reference do not match

Error message: SQLSTATE[42000]: Syntax error or access violation: 1239 Incorrect foreign key definition for 'fk.faq.product_id': key reference and table reference do not match product table: CREATE TABLE `product` (`id` BINARY( 16) NOT NULL, `version_id` BINARY(16) NOT NULL, `created_

P粉798010441 2023-07-18 15:17:02 1  1  692

Is JavaScript a pass-by-reference or pass-by-value language?

Primitive types (numbers, strings, etc.) are passed by value, but objects are unknown, since they can all be passed by value (in which case we think the variable holding the object is actually a reference) and pass-by-reference (when we think of an object's variables as holding the object itself). A...

P粉450744515 2023-08-23 18:58:12 0  1  545

Is JavaScript a language that uses pass-by-reference or pass-by-value?

Primitive types (numbers, strings, etc.) are passed by value, but objects are unknown since they can all be passed by value (in this case, the variable we think holds the object is actually a reference to the object) and pass-by-reference (when we think of an object's variables as holding the object...

P粉002546490 2023-10-11 17:50:30 0  1  749

Rails created_at index unused index

I have a model called CacheSync and mysql shows it has an index: mysql>showindexesfromcache_syncs;+-------------+------------+-- ----------------------------------+--------------+--- ----------+-----------+-------------+----------+-- -

P粉384679266 2024-03-21 23:40:41 0  1  373