Posts (page 83)
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6 min readProperty delegates in Kotlin are a powerful feature that allows you to add functionality to the getter and setter methods of a property. To work with property delegates, you first need to define a class that implements the ReadOnlyProperty interface for read-only properties or the ReadWriteProperty interface for read-write properties.Next, you can use the by keyword when declaring a property to delegate its operations to an instance of the delegate class.
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5 min readSealed classes in Kotlin are special classes that restrict the inheritance hierarchy of a class. They can only have a fixed set of subclasses, which are defined within the sealed class itself. This allows you to create a closed type hierarchy, ensuring that all possible subclasses are known at compile time.When working with sealed classes in Kotlin, you can use them in pattern matching expressions with the when keyword.
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5 min readIn Kotlin, inline functions are a way to improve performance by removing the overhead of function calls. When you mark a function as inline, the compiler will copy the function code directly into the calling code, reducing the extra work needed to call the function.To use inline functions, declare the function using the keyword "inline" before the function keyword. This tells the compiler to inline the function, removing the function call overhead.
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5 min readTo merge two rows into one row in pandas, you can use the groupby() function along with the agg() function to concatenate or combine the values of the two rows. First, you need to group the rows based on a certain key or condition using the groupby() function. Then, you can use the agg() function to apply a specific aggregation function, such as join() or sum(), to merge the two rows into one row. Finally, you can reset the index of the resulting DataFrame to have a single row for each group.
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4 min readType aliases in Kotlin provide a way to create alternative names for existing types. They are mainly used to simplify complex type declarations or to make the code more readable and maintainable.To create a type alias in Kotlin, you can use the typealias keyword followed by the desired alias name and the type you want to alias.
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3 min readTo load a text file into pandas, you can use the read_csv() function which is capable of reading various file formats including text files. Make sure to specify the delimiter and other necessary parameters according to the structure of your text file. Additionally, you can specify the file path and any other optional parameters to customize the loading process. Once the file has been read into a pandas DataFrame, you can perform various data manipulation and analysis tasks on the data.
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4 min readIn Kotlin, data classes are special classes that are used to represent data. They are typically used to hold and manage data in a concise and efficient manner. To define a data class in Kotlin, you simply need to use the "data" keyword before the class declaration. This tells the compiler that the class is a data class and provides some additional functionality.Data classes automatically provide implementations for commonly used methods such as toString(), equals(), and hashCode().
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3 min readTo replace pandas append with concat, you can use the pd.concat() function instead. This function combines DataFrames along a particular axis, allowing you to concatenate multiple DataFrames into one. Simply pass a list of DataFrames to pd.concat() and specify the axis along which you want to concatenate them (0 for rows, 1 for columns). This way, you can avoid using the append method and achieve the same result more efficiently.
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3 min readAnnotations in Kotlin are a way to add metadata to your code. They are used to provide additional information about the code to the compiler or runtime environment. Annotations in Kotlin are declared with the '@' symbol followed by the name of the annotation.To use an annotation in Kotlin, you simply place the annotation before the element you want to annotate.
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4 min readTo make a custom sum in pandas, you can use the apply() function along with a custom function that defines how you want to calculate the sum.First, create a custom function that takes a Series as input and returns the sum according to your custom logic. For example, you may want to exclude certain values from the sum or apply a specific formula.After defining your custom function, you can use the apply() function on a DataFrame column to calculate the custom sum.
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6 min readCoroutines in Kotlin provide a way to perform asynchronous and non-blocking programming. By using coroutines, you can write asynchronous code in a sequential and easier to read manner. To work with coroutines in Kotlin, you first need to include the kotlinx.coroutines library in your project. You can create a coroutine using the launch or async functions and define its behavior using a suspending function.
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3 min readYou can get a range of dates in a column in pandas by using the pd.date_range() function. You can specify the start date, end date, and frequency of the dates you want to generate. For example, if you want to create a range of dates from January 1, 2021 to January 10, 2021 with a frequency of 1 day, you can use the following code: import pandas as pd start_date = '2021-01-01' end_date = '2021-01-10' date_range = pd.