10 recommended articles about unique

Our last article talked about "How to delete the head, tail, and any element in a PHP array." In this article, we talk about deleting duplicate elements in the array through the array_unique() function. The array_unique() function sorts the values ​​of the array elements as strings, and then only retains the first key name for each value and ignores all subsequent key names, which is to delete duplicate elements in the array. The syntax format is as follows: array arry_unique( array array) The parameter array is the input array. The following example uses the array_unique() function to delete duplicate elements in the array. The specific example code is as follows:

1. Recommended 10 articles about array_unique()

Introduction: Our previous article talked about "How to delete the head, tail, and any element in a PHP array". In this article we will talk about Use the array_unique() function to delete duplicate elements in the array. The array_unique() function sorts the values ​​of the array elements as strings, and then only retains the first key name for each value and ignores all subsequent key names, which is to delete the array. For repeated elements, the syntax format is as follows: array arry_unique(array array) The parameter array is the input array...

2. Articles about the php array_unique() function Recommended 10 articles

Introduction: Our last article talked about "How to delete the header in a PHP array , tail, any element", in this article we describe how to delete duplicate elements in the array through the array_unique() function. The array_unique() function sorts the values ​​of the array elements as strings, and then only retains the first key name for each value and ignores it. All subsequent key names are to delete duplicate elements in the array. The syntax format is as follows: array arry_unique(array array) The parameter array is the input array...

##3. Detailed introduction to how MySQL uses UNIQUE to achieve non-duplicate data insertion

Introduction: When unique columns When inserting records containing duplicate values ​​on a UNIQUE key, we can control how MySQL handles this situation: use the IGNORE keyword or the ON DUPLICATE KEY UPDATE clause to skip the INSERT, interrupt the operation, or update the old record with the new value ##.

#4.

Analysis of three commonly used insert statements in mysql and their differences

##Introduction: Three commonly used statements for inserting data in mysql: insert into means inserting data, the database will check the primary key (PrimaryKey), and an error will be reported if there is a duplicate; replace into means inserting replacement data, in the demand table If there is a PrimaryKey or unique index, if the data already exists in the database, it will be replaced with new data. If there is no data, the effect will be the same as insert into; the REPLACE statement will return a number to indicate the impact

5.

How to delete duplicate elements in a PHP array

##Introduction: array_unique( ) function, sorts the values ​​of the array elements as strings, and then retains only the first key name for each value and ignores all subsequent key names, which is to delete duplicate elements in the array,

6. Detailed explanation of how Python uses the UUID library to generate unique ID examples

Introduction: UUID introduction UUID is a 128-bit globally unique identifier, usually represented by a 32-byte string. It can ensure the uniqueness of time and space, also called GUID, the full name is: UUID - Universally Unique IDentifier, called UUID in Python. It uses MAC address, timestamp, namespace, random number, and pseudo-random number to ensure the uniqueness of the generated ID. UUID mainly has five algorithms, that is, five

7. MySQL-Introduction to Several Ways to Add Indexes

Introduction: 1. Add PRIMARY KEY (primary key index) mysql>ALTER TABLE `table_name` ADD PRIMARY KEY ( `column` ) 2. Add UNIQUE (unique Index) mysql>ALTER TABLE `table_name` ADD UNIQUE ( `column` ) 3. Add INDEX (normal index) mysql>ALTER TABLE `t

8. Share a MySQL Methods to solve the deadlock problem

## Introduction: Share a method to solve the MySQL deadlock problem, try to pass The two fields of tel_id and task_id establish UNIQUE (unique index) to solve

9. Detailed introduction of the code to solve the MySQL deadlock problem

#Introduction: Based on this analysis, try to solve the problem by establishing a UNIQUE (unique index) through the two fields of tel_id and task_id. (You can also query it first and then update it based on the primary key ID, so that the large amount of data in the table will not affect online business).

10. C++11 new features smart pointers (shared_ptr/unique_ptr/weak_ptr)

Introduction: This article mainly introduces the new features of C++11 smart pointers, including the basic use of shared_ptr, unique_ptr and weak_ptr. Interested friends can refer to it.

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