Programmer Think

1. $pull modifier deletes qualifying elements from the array in the following format: { $pull: { <field1>: <value|condition>, <field2>: <value|condition>, ... } } 2. Specify a value to delete all lists Give a document under a stores collection { _id: 1, fruits: [ "apples", "pears", "oranges", "grapes", "bana ...

Spring boot for multi data source configuration springBoot implements the configuration of multiple data sources application.properties Configure two data sources in spring.datasource.primary.url=jdbc:mysql://localhost:3306/test1 spring.datasource.primary.username=root spring.datasource.primary.password=root spring.datasource.primary.driv ...

In integer arrays, we need to get the maximum and minimum values of array elements from them: Method 1: Sort using Array first, then from the sorted array, the first element is the smallest and the last element is the largest.   public static int FindMaxNumber(params int[] stringValue) { Array.Sort(stringV ...

thread The thread module of python is a lower level module, and the threading module of python is a package for thread, which can be used more conveniently Using the threading module Single thread execution #coding=utf-8 import time def saySorry(): print("Honey, I'm wrong. Can I eat now?") time.sleep(1) if __name__ == "__main__": ...

Jurisdiction <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"></uses-permission> <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"></uses-permission> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></u ...