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In this article, we will take an example and demonstrate the difference between (!!) and (?) in Kotlin.Example – "!!" and "?" operator in KotlinKotlin provides a wonderful operator to check NULL pointer exceptions. It throws a NULL pointer exception instead of breaking the programming logic whenever the variable is NULL.In the following example, the value of "test" is NULL. Hence, Kotlin will throw a NULL pointer exception instead of breaking down the logic. The example shows the different uses of "!!" and "?" operators.fun main(args: Array) { val nullValue: String ?=null // it will print null ... Read More
Exception is an important aspect of any programming language. It prevents our code from generating incorrect output at runtime. There are two types of exceptions −Checked exceptionsUnchecked exceptionsChecked ExceptionsChecked exceptions are those which are checked at the compile time. As per example, FileNotFoundException() or IOException. In the following example, we will see how we can generate a checked Exception.Exampleimport java.io.File import java.io.InputStream fun main(args: Array) { try { val inputStream: InputStream = File("Hello.txt").inputStream() } catch(e:Exception) { e.printStackTrace(); } }OutputOnce you execute this code, it will generate the following output in ... Read More
Data class is a collection in Kotlin to store data. Logically this is same as creating a Java POJO class. In Java, we do create extra member functions to set and get the data in the member variables. In Kotlin, we don’t need to create separate methods to access the member variables of the class. Kotlin provides it by default. We can access the variables by just using the member variable names in it.It is not recommended to override any of the data class members like we used to do in Java.It is always recommended to use normal class if ... Read More
To return the cumulative product of array elements over a given axis treating NaNs as one, use the nancumprod() method. The cumulative product does not change when NaNs are encountered and leading NaNs are replaced by ones. Ones are returned for slices that are all-NaN or empty. The method returns a new array holding the result is returned unless out is specified, in which case it is returned. Cumulative works like, 5, 5*10, 5*10*15, 5*10*15*20The 1st parameter is the input array. The 2nd parameter is the Axis along which the cumulative product is computed. By default the input is flattened. ... Read More
To return a boolean array which is True where the string element in array ends with suffix, use the numpy.char.endswith() method in Python Numpy. The first parameter is the input array. The second parameter is the suffix. The numpy.char module provides a set of vectorized string operations for arrays of type numpy.str_StepsAt first, import the required libraries −import numpy as npCreate a One-Dimensional array of strings −arr = np.array(['KATIE', 'JOHN', 'KATE', 'AmY', 'BRADley'])Displaying our array −print("Array...", arr)Get the datatype −print("Array datatype...", arr.dtype)Get the dimensions of the Array −print("Array Dimensions...", arr.ndim)Get the shape of the Array −print("Our Array Shape...", arr.shape)Get the ... Read More
To get the Inner product of two arrays, use the numpy.inner() method in Python. Ordinary inner product of vectors for 1-D arrays, in higher dimensions a sum product over the last axes. The parameters are 1 and b, two vectors. If a and b are nonscalar, their last dimensions must match.StepsAt first, import the required libraries −import numpy as npCreating two numpy One-Dimensional array using the array() method −arr1 = np.array([5, 10, 15]) arr2 = np.array([20, 25, 30])Display the arrays −print("Array1...", arr1) print("Array2...", arr2)Check the Dimensions of both the arrays −print("Dimensions of Array1...", arr1.ndim) print("Dimensions of Array2...", arr2.ndim)Check the Shape ... Read More
To return the dot product of One-Dimensional vectors, use the numpy.vdot() method in Python. The vdot(a, b) function handles complex numbers differently than dot(a, b). If the first argument is complex the complex conjugate of the first argument is used for the calculation of the dot product. The vdot handles multidimensional arrays differently than dot: it does not perform a matrix product, but flattens input arguments to 1-D vectors first. Consequently, it should only be used for vectors.The method returns the dot product of a and b. Can be an int, float, or complex depending on the types of a ... Read More
To return the dot product of two multi-dimensional vectors, use the numpy.vdot() method in Python. The vdot(a, b) function handles complex numbers differently than dot(a, b). If the first argument is complex the complex conjugate of the first argument is used for the calculation of the dot product. The vdot handles multidimensional arrays differently than dot: it does not perform a matrix product, but flattens input arguments to 1-D vectors first. Consequently, it should only be used for vectors.The method returns the dot product of a and b. Can be an int, float, or complex depending on the types of ... Read More
To return the dot product of two vectors, use the numpy.vdot() method in Python. The vdot(a, b) function handles complex numbers differently than dot(a, b). If the first argument is complex the complex conjugate of the first argument is used for the calculation of the dot product. The vdot handles multidimensional arrays differently than dot: it does not perform a matrix product, but flattens input arguments to 1-D vectors first. Consequently, it should only be used for vectors.The method returns the dot product of a and b. Can be an int, float, or complex depending on the types of a ... Read More
To compute the inverse hyperbolic tangent with arctanh, use the numpy.emath.arctanh() method in Python. Returns the “principal value” of arctanh(x). For real x such that abs(x) < 1, this is a real number. If abs(x) > 1, or if x is complex, the result is complex. Finally, x = 1 returns``inf`` and x=-1 returns -inf.The method returns the inverse hyperbolic tangent(s) of the x value(s). If x was a scalar so is out, otherwise an array is returned. The 1st parameter is the value(s) whose arctanh is (are) required.StepsAt first, import the required libraries −import numpy as npCreate a numpy ... Read More