Posts (page 68)
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3 min readTo increment rows by 1 from a certain range in PostgreSQL, you can use the UPDATE statement with a WHERE clause to specify the range of rows you want to increment.
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5 min readTo show years in the x-axis using matplotlib, you need to first convert the datetime format of your data into a format that matplotlib understands. You can do this by using the DateFormatter class from the matplotlib library. Simply create a DateFormatter object with the desired format for the x-axis (e.g. '%Y' for years only), and then apply this DateFormatter to the x-axis using the set_major_formatter method of the Axis object.
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3 min readTo get a custom assembly attribute with PowerShell, you can use the System.Reflection.Assembly class. First, load the assembly using the LoadFile method. Then, use the GetCustomAttributes method to retrieve the custom attributes from the assembly. You can specify the type of attribute you are looking for by passing the attribute class type as a parameter to the GetCustomAttributes method.
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6 min readTo add a title for a subgroup of subplots in matplotlib, you can create a title for the specific subplot group by selecting the axes of that group and using the set_title() method to set the title. This way, you can customize and label each subgroup of subplots with their respective titles to effectively organize and present your data in the matplotlib visualization.[rating:b1c44d88-9206-437e-9aff-ba3e2c424e8f]What options are available for styling the title of a subplot in matplotlib.
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5 min readWhen optimizing PostgreSQL joins based on time ranges, it is important to consider a few key factors. One approach is to ensure that you have appropriately defined indexes on the columns involved in the join conditions, such as time range columns. This can help to speed up the query processing by allowing PostgreSQL to efficiently locate the relevant data.
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5 min readTo check open ports using PowerShell, you can use the Test-NetConnection cmdlet. This cmdlet allows you to test a connection to a specific port on a remote computer.To check if a port is open on a specific remote computer, you can use the following command: Test-NetConnection -ComputerName REMOTE_COMPUTER -Port PORT_NUMBER Replace REMOTE_COMPUTER with the name or IP address of the remote computer and PORT_NUMBER with the port number you want to check.
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5 min readTo create a candlestick chart using matplotlib, you first need to import the necessary libraries, such as matplotlib, matplotlib.finance, and matplotlib.dates. Next, you would read in your financial data and convert it into a format that is compatible with matplotlib. Then, you can use the candlestick_ohlc function to plot the candlestick chart based on your data. Make sure to customize your chart by adding labels, titles, and adjusting the colors and styles of the candlesticks as needed.
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3 min readTo add a child element for XML in PowerShell, you can use the SelectSingleNode method to locate the parent node to which you want to add the child element. Once you have selected the parent node, you can use the AppendChild method to create and add a new child element to it. You can specify the name and value of the child element using the CreateElement method. Finally, you can save the updated XML document using the Save method.
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6 min readTo perform a wildcard search in PostgreSQL, you can use the LIKE keyword along with % and _ symbols as wildcard characters. The % symbol represents zero or more characters, while the _ symbol represents a single character. For example, if you want to search for all values that start with "abc", you can use WHERE column_name LIKE 'abc%'. Similarly, if you want to search for values that end with "xyz", you can use WHERE column_name LIKE '%xyz'.
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7 min readTo create a 2D color gradient plot using matplotlib, you can start by importing the necessary libraries such as matplotlib and numpy. Next, you can create a 2D grid using numpy's meshgrid function. Then, you can use matplotlib's imshow function to display the grid as a color gradient plot. You can customize the color gradient by setting the cmap parameter to a desired color map such as 'viridis' or 'coolwarm'.
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4 min readTo send date/time to a COM port via PowerShell, you can first open the COM port using the .NET SerialPort class. You will need to specify the COM port number, baud rate, data bits, parity, and stop bits. Once the port is open, you can use the Write method to send the current date and time as a string to the COM port. Remember to close the port after sending the data to release the resources.
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8 min readTo detect changes in a PostgreSQL database with Node.js, you can use the pg-pubsub library. This library allows you to subscribe to specific table events such as INSERT, UPDATE, and DELETE. By listening to these events, you can detect changes in the database in real-time and trigger actions accordingly.To use pg-pubsub, you first need to install the library using npm:npm install pg-pubsubNext, you can create a new instance of pg-pubsub and subscribe to specific table events using the on method.