Posts (page 83)
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4 min readTo request an available port to the operating system in Rust, you can use the TcpListener type from the standard library. TcpListener allows you to bind to a specific address and port, and then listen for incoming TCP connections on that port.You can create a new TcpListener instance by calling TcpListener::bind, passing in the address and port you want to bind to. This will return a Result<TcpListener, Error> which you can then unwrap to get the TcpListener instance.
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3 min readIn PostgreSQL, you can use the ARRAY function to convert a key-value pair from a JSON object into an array. Here's an example of how to inverse a key to an array: SELECT ARRAY(SELECT json_object_keys('{"name": "John", "age": 30}') AS key); This query will return an array with the keys of the JSON object, in this case, it would return: ['name', 'age'].
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5 min readOne way to shuffle a TensorFlow dataset without using a buffer is to use the shuffle method. This method takes an argument buffer_size that specifies the number of elements from the dataset to sample when shuffling. By setting buffer_size to be the same as the total number of elements in the dataset, you effectively shuffle the entire dataset.To shuffle a TensorFlow dataset without a buffer, you can use the following code snippet: dataset = tf.data.Dataset.
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4 min readTo call a JSON parameter in a PostgreSQL procedure, you can define the input parameter of the procedure as type JSON. Inside the procedure, you can then access the JSON data using the predefined operators and functions provided by PostgreSQL for working with JSON data. This allows you to manipulate and extract information from the JSON object passed as a parameter to the procedure.
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6 min readTo upload a PNG or JPG file to a PostgreSQL database using Python, you can use the psycopg2 library to interact with the database. First, you need to read the image file as binary data using the open() function in Python. Next, you can insert the binary data into a bytea column in the PostgreSQL table using an INSERT statement with a parameterized query. Make sure to escape any special characters in the binary data before inserting it into the database.
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6 min readt-SNE is a dimensionality reduction technique commonly used in machine learning and data visualization to reduce high-dimensional data to a lower-dimensional representation for visualization and clustering purposes.To implement t-SNE in TensorFlow, you can use the tf.contrib.learn.embeddings.tSNE function provided by TensorFlow's contrib library. First, you need to prepare your data and define a TensorFlow graph that includes the t-SNE operation.
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5 min readWhen casting a float to a numeric data type in PostgreSQL, the float value is converted to a numeric value with the specified precision and scale. The precision determines the maximum number of digits that can be stored before and after the decimal point, while the scale determines the number of digits allowed after the decimal point.During the casting process, PostgreSQL will round the float value to fit the specified precision and scale of the numeric data type.
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7 min readTo query parent-child relationships in PostgreSQL, you can use a self-join on the same table using a recursive query with the "WITH RECURSIVE" clause. This allows you to retrieve hierarchical data by following relationships between parent and child rows in the same table. By joining the table with itself based on the parent-child relationship, you can navigate through the hierarchy and retrieve the desired data.
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4 min readIn order to add a trainable variable in Python TensorFlow, you can use the tf.Variable class and set the trainable parameter to True. By doing so, the variable will be included in the computational graph and its values will be updated during training using gradient descent or other optimization algorithms. This allows you to define and optimize custom parameters or weights in your neural network models.
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4 min readIn PostgreSQL, you can update a table without using a subquery by using a join with the target table in the UPDATE statement. This allows you to set values in the target table based on conditions or values from other tables. You can specify the join condition in the UPDATE statement to determine which rows should be updated, and then set the values you want for those rows.
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5 min readTo deadlock an insert query in PostgreSQL, you would need to have at least two transactions simultaneously trying to insert data into the same table. Each transaction would need to have acquired a lock on different resources (such as rows or tables) in a conflicting order, causing them to wait for each other indefinitely.One common way to deliberately create a deadlock situation is to have two transactions lock rows in different orders.
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6 min readTo understand TensorFlow predictions, you first need to have a basic understanding of how TensorFlow works. TensorFlow is an open-source machine learning library developed by Google that is often used for building and training deep learning models. When you make predictions using a trained TensorFlow model, the model takes in input data and processes it through its neural network to produce an output.To interpret these predictions, you need to understand the format of the output data.