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Page 1090 of 2109
Create a DataFrame with customized index parameters in Pandas
To create a DataFrame with some index, we can pass a list of values and assign them into index in DataFrame Class.StepsCreate a two-dimensional, size-mutable, potentially heterogeneous tabular data, df.Put a list of indices in the index of DataFrame class.Print the DataFrame with the customized index.Exampleimport pandas as pd df = pd.DataFrame( { "x": [5, 2, 1, 9], "y": [4, 1, 5, 10], "z": [4, 1, 5, 0] } ) print "Input DataFrame is:", df df = pd.DataFrame( { "x": [5, 2, 1, 9], "y": [4, 1, 5, 10], "z": [4, 1, 5, 0] }, index=["John", "Jacob", "Ally", "Simon"] ) print "With Customized Index: ", dfOutputInput DataFrame is: x y z 0 5 4 4 1 2 1 1 2 1 5 5 3 9 10 0 With Customized Index: x y z John 5 4 4 Jacob 2 1 1 Ally 1 5 5 Simon 9 10 0
Read MoreHow to check if a column exists in Pandas?
To check if a column exists in a Pandas DataFrame, we can take the following Steps −StepsCreate a two-dimensional, size-mutable, potentially heterogeneous tabular data, df.Print the input DataFrame, df.Initialize a col variable with column name.Create a user-defined function check() to check if a column exists in the DataFrame.Call check() method with valid column name.Call check() method with invalid column name.Exampleimport pandas as pd def check(col): if col in df: print "Column", col, "exists in the DataFrame." else: print "Column", col, "does not exist in the DataFrame." df = pd.DataFrame( ...
Read MoreCount the frequency of a value in a DataFrame column in Pandas
To count the frequency of a value in a DataFrame column in Pandas, we can use df.groupby(column name).size() method.StepsCreate a two-dimensional, size-mutable, potentially heterogeneous tabular data, df.Print the input DataFrame, df.Print frequency of column, x.Print frequency of column, y.Print frequency of column, z.Exampleimport pandas as pd df = pd.DataFrame( { "x": [5, 2, 1, 5], "y": [4, 10, 5, 10], "z": [1, 1, 5, 1] } ) print "Input DataFrame is:", df col = "x" count = df.groupby('x').size() print "Frequency of values in column ", col, "is:", ...
Read MoreHow to use the apply() function for a single column in Pandas?
We can use apply() function on a column of a DataFrame with lambda expression.StepsCreate a two-dimensional, size-mutable, potentially heterogeneous tabular data, df.Print input DataFrame, df.Override column x with lambda x: x*2 expression using apply() method.Print the modified DataFrame.Exampleimport pandas as pd df = pd.DataFrame( { "x": [5, 2, 1, 5], "y": [4, 10, 5, 10], "z": [1, 1, 5, 1] } ) print "Input DataFrame is:", df df['x'] = df['x'].apply(lambda x: x * 2) print "After applying multiplication of 2 DataFrame is:", dfOutputInput DataFrame is: x y z 0 5 4 1 1 2 10 1 2 1 5 5 3 5 10 1 After applying multiplication of 2 DataFrame is: x y z 0 10 4 1 1 4 10 1 2 2 5 5 3 10 10 1
Read MoreHow to sort multiple columns of a Pandas DataFrame?
To sort multiple columns of a Pandas DataFrame, we can use the sort_values() method.StepsCreate a two-dimensional, size-mutable, potentially heterogeneous tabular data, df.Print the input DataFrame, df.Initialize a variable col to sort the column.Print the sorted DataFrame.Exampleimport pandas as pd df = pd.DataFrame( { "x": [5, 2, 7, 0], "y": [4, 7, 5, 1], "z": [9, 3, 5, 1] } ) print "Input DataFrame is:", df col = ["x", "y"] df = df.sort_values(col, ascending=[False, True]) print "After sorting column ", col, "DataFrame is:", dfOutputInput DataFrame is: x y z 0 5 4 9 1 2 7 3 2 7 5 5 3 0 1 1 After sorting column ['x', 'y'] DataFrame is: x y z 2 7 5 5 0 5 4 9 1 2 7 3 3 0 1 1
Read MoreHow to find the sum of numbers stored in character vector separated with a special character in R?
To find the sum of numbers stored in character vector separated with a special character in R, we can follow the below steps −First of all, create a vector having numbers stored in character vector separated with a special character.Then, use sapply and strsplit function to find the sum of numbers.Example1Create a vector with numbers stored in character vector separated with hyphen −> x1 x1On executing, the above script generates the below output(this output will vary on your system due to randomization) − [1] "11-2-15-19-10" "11-2-15-19-10" "13-12-75-29-18" "15-25-52-91-10" [5] "15-25-52-91-10" "17-27-55-91-100" "13-12-75-29-18" "15-25-52-91-10" [9] "13-12-75-29-18" "10-4-5-19-10" "17-27-55-91-100" ...
Read Morek-Rough Number or k-Jagged Number in C++
In this tutorial, we are going to write a program that checks whether the given number is k-rough or k-jagged number or not.The number whose smallest prime factor is greater than or equal to the given k, it is called k-rough or k-jagged number.Let's see the steps to solve the problem.Initialise the numbers n and k.Find all the prime numbers that are factors of n and store them in a vector.Get the first element from the vector and compare it with k to check whether n is k-rough or k-jagged number or not.ExampleLet's see the code.#include using namespace std; ...
Read MoreK-th digit in 'a' raised to power 'b' in C++
In this tutorial, we are going to write a program that finds the k-th digit from the right side in the number abIt's a straightforward problem. Let's see the steps to solve it.Initialise the numbers a, b, and k.Find the value of abusing pow method.Write a loop that iterates until power value is less than zero or count is less than k.Get the last digit from the power value.Increment the counter.Check whether k and counter are equal or not.Return the digit if they are equalReturn -1.ExampleLet's see the code.#include using namespace std; int getTheDigit(int a, int b, int k) ...
Read MoreK-th Element of Two Sorted Arrays in C++
In this tutorial, we are going to write a program that finds the k-th element from thee merged array of two sorted arrays.Let's see the steps to solve the problem.Initialise the two sorted arrays.Initialise an empty array of size m + n.Merge the two arrays into the new array.Return the k - 1 element from the merged array.ExampleLet's see the code.#include using namespace std; int findKthElement(int arr_one[], int arr_two[], int m, int n, int k) { int sorted_arr[m + n]; int i = 0, j = 0, index = 0; while (i < m && j ...
Read MoreK-th Greatest Element in a Max-Heap in C++
In this tutorial, we are going to write a program that finds the k-th largest element from the max-heap.We will use priority queue to solve the problem. Let's see the steps to complete the program.Initialise the max-heap with correct values.Create a priority queue and insert the root node of the max-heap.Write a loop that iterates k - 1 times.Pop the greatest element from the queue.Add the left and right nodes of the above node into the priority queue.The greatest element in priority queue is the k-th greatest element now.Return it.ExampleLet's see the code.#include using namespace std; struct Heap { ...
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