Python Articles - Page 825 of 929

In Pandas a DataFrame is a two-dimensional data structure, i.e., data is aligned in a tabular fashion in rows and columns. We can create a DataFrame using list, dict, series and another DataFrame. But when we want to add a new row to an already created DataFrame, it is achieved through a in-built method like append which add it at the end of the DataFrame. In this article we will find ways to add the new row DataFrame at the top of the DataFrame using some tricks involving the index of the elements in the DataFrame.ExampleLet's first create a new ... Read More

In this article, we will learn about some of the inplace operators available in Python 3.x. Or earlier.Python provides methods to perform inplace operations, i.e assignment and computation simultaneously using in a single statement with the help of “operator” module. Here we will discuss about ixor(), iand(), ipow() functions .ixor()This function allows us to assign and xor current value. This operation behaves like “a^=b” operation. Assigning can’t be performed in case of immutable data types, such as strings and tuples.Exampleimport operator as op # using ixor() to xor int1 = op.ixor(786, 12); # displaying value print ("The value ... Read More

In statistics, the term "frequency" indicates the number of occurrences of a value in a given data sample. As a software meant for mathematical and scientific analysis, Pandas has many in-built methods to calculate frequency from a given sample.Absolute Frequency It is same as just the frequency where the number of occurrences of a data element is calculated. In the below example, we simply count the number of times the name of a city is appearing in a given DataFrame and report it out as frequency.Approach 1 − We use the pandas method named .value_counts.Exampleimport pandas as pd # Create ... Read More

In this article, we will learn about how we can initialize matrix using two dimensional list in Python 3.x. Or earlier.Let’s see the intuitive way to initialize a matrix that only python language offers. Here we take advantage of List comprehension. we initialise the inner list and then extend to multiple rows using the list comprehension.Example# input the number of rows N = 3 # input the number of columns M = 3 # initializing the matrix res = [ [ i*j for i in range(N) ] for j in range(M) ] # printing the matrix on screen row ... Read More

In Statistical analysis study of data variability in a sample indicates how dispersed are the values in a given data sample. The two important ways we calculate the variability are Absolute Deviation and  Mean Absolute Deviation.Absolute DeviationIn this method we first find the mean value of the given sample and then calculate the difference between each value and the mean value of the sample called as the absolute deviation value of each data sample. So for the values higher than mean the value the deviation value will be positive and for those lower than the mean value the deviation value ... Read More

In this chapter we see what happens when we update the values in a tuple, which is actually immutable. We will be able to merge new values with old values but that throws an error. We can study the bytecode of the error and understand better how the rules for tuple work.First we define a tuple and then issue a command to update its last element as shown below.Example>>> tupl = (5, 7, 9, [1, 4]) >>> tupl[3] += [6, 8]OutputRunning the above code gives us the following result −Traceback (most recent call last): File "", line 1, in TypeError: ... Read More

In this article, we will see how to extract details about Youtube videos and download them in different formats using the pafy module. Head over to the link for official documentation.Install the pafy module using the following commandpip install pafyIf you run the above command, it will generate the following results on the successful installation of the module pafy.Collecting pafy Using cached https://files.pythonhosted.org/packages/b0/e8/3516f761558525b00d3eaf73744eed5c267db 20650b7b660674547e3e506/pafy-0.5.4-py2.py3-none-any.whl Installing collected packages: pafy Successfully installed pafy-0.5.4Check whether you can import the pafy module or not by running the following command.import pafyIf you found no errors then it's done. Otherwise install the following module to solve ... Read More

When we define a function in a python program, the purpose is to execute the code again and again by supplying different values to the function's arguments. One challenge in this design is, what if we are not sure about the number of arguments we want to process each time we call that function. This is where the special arguments called **args and **kwargs are needed. Let's look at them one by one.*argsThe *args enables us to use variable number of arguments as input to the function. In the below example we are finding out the result of multiplication of ... Read More

Many times when we create python code we find that we need to access code from another python file or package. This is when you need to import that other python file or package into your current code. So the straight forward way to achieve this is just written the below statement at the top of your current python program.import package_name or module_name or from pacakge_name import module_name/object_nameWhen the above statement is parsed the interpreter does the following.The interpreter will look for names in the cache of all modules that have already been imported previously. The name of this cache ... Read More

Ordering of data elements in a specific order is a frequently needed operation. To sort elements in an array, python uses the functions named sorted() and array.sort().sorted(array)This function returns a sorted array without modifying the original array.a = [9, 5, 3, 1, 12, 6] b = sorted([9, 5, 3, 1, 12, 6]) print "Sorted Array :", print (b) print "Original Array :", print (a)Running the above code gives us the following result −Sorted Array : [1, 3, 5, 6, 9, 12] Original Array : [9, 5, 3, 1, 12, 6]list.sort()The sort function returns a sorted array by doing in-place modification ... Read More