When it is required to filter dictionaries by values in ‘K’th key in a list, a simple iteration by specifying the condition is used.ExampleBelow is a demonstration of the samemy_list = [{"Python": 2, "is": 4, "cool": 11}, {"Python": 5, "is": 1, "cool": 1}, {"Python": 7, "is": 3, "cool": 7}, {"Python": 9, "is": 9, "cool": 8}, {"Python": 4, "is": 10, "cool": 6}] print("The list is :") print(my_list) search_list = [1, 9, 8, 4, 5] key = "is" my_result = [] for sub in my_list: ... Read More

When it is required to find the most common combination in a matrix, a simple iteration, along with the ‘sort’ method and ‘Counter’ method is used.ExampleBelow is a demonstration of the samefrom collections import Counter from itertools import combinations my_list = [[31, 25, 77, 82], [96, 15, 23, 32]] print("The list is :") print(my_list) my_result = Counter() for elem in my_list:    if len(elem) < 2:       continue    elem.sort()    for size in range(2, len(elem) + 1):       for comb in combinations(elem, size):          my_result[comb] += ... Read More

To Groupby value counts, use the groupby(), size() and unstack() methods of the Pandas DataFrame. At first, create a DataFrame with 3 columns −dataFrame = pd.DataFrame({    'Product Category': ['Computer', 'Mobile Phone', 'Electronics', 'Electronics', 'Computer', 'Mobile Phone'], 'Product Name': ['Keyboard', 'Charger', 'SmartTV', 'Camera', 'Graphic Card', 'Earphone'], 'Quantity': [10, 50, 10, 20, 25, 50]}) Now, groupby values count with groupby() method. For count, use the size() and unstack(). The unstack() gives a new level of column labels −dataFrame = dataFrame.groupby(['Product Category', 'Product Name', 'Quantity']).size().unstack(fill_value=0)ExampleFollowing is the complete code −import pandas as pd # create a dataframe with 3 columns ... Read More

When it is required to get all pairwise combinations from a list, an iteration along with the ‘append’ method is used.ExampleBelow is a demonstration of the samemy_list = [15, "John", 2, "Will", 53, 'Rob'] print("The list is :") print(my_list) my_result = [] for i in range(0, len(my_list)): for j in range(0, len(my_list)): if (i!=j): my_result.append((my_list[i], my_list[j])) print("The result is :") print(my_result)OutputThe list is : [15, 'John', 2, 'Will', 53, 'Rob'] The result is : [(15, 'John'), (15, ... Read More

When it is required to find unique values count of every key, an iteration along with the ‘append’ method is used.ExampleBelow is a demonstration of the samemy_list = [12, 33, 33, 54, 84, 16, 16, 16, 58] print("The list is :") print(my_list) filtered_list = [] elem_count = 0 for item in my_list: if item not in filtered_list: elem_count += 1 filtered_list.append(item) print("The result is :") print(elem_count)OutputThe list is : [12, 33, 33, 54, 84, 16, 16, 16, 58] The result ... Read More

When it is required to mark duplicate elements in a string, list comprehension along with the ‘count’ method is used.ExampleBelow is a demonstration of the samemy_list = ["python", "is", "fun", "python", "is", "fun", "python", "fun"] print("The list is :") print(my_list) my_result = [value + str(my_list[:index].count(value) + 1) if my_list.count(value) > 1 else value for index, value in enumerate(my_list)] print("The result is :") print(my_result)OutputThe list is : ['python', 'is', 'fun', 'python', 'is', 'fun', 'python', 'fun'] The result is : ['python1', 'is1', 'fun1', 'python2', 'is2', 'fun2', 'python3', 'fun3']ExplanationA list is defined and is displayed on the console.The list comprehension ... Read More

To calculate the count of column values, use the count() method. At first, import the required Pandas library −import pandas as pdCreate a DataFrame with two columns −dataFrame1 = pd.DataFrame( { "Car": ['BMW', 'Lexus', 'Audi', 'Tesla', 'Bentley', 'Jaguar'], "Units": [100, 150, 110, 80, 110, 90] } )Finding count of "Units" column values using the count() function −print"Count of values of Units column from DataFrame1 = ", dataFrame1['Units'].count() In the same way, we have calculated the count from the 2nd DataFrame.ExampleFollowing is the ... Read More

When it is required to index directory of elements in a list, list comprehension along with ‘set’ operator is used.ExampleBelow is a demonstration of the samemy_list = [81, 36, 42, 57, 68, 12, 26, 26, 38] print("The list is :") print(my_list) my_result = {key: [index for index, value in enumerate(my_list) if value == key] for key in set(my_list)} print("The result is :") print(my_result)OutputThe list is : [81, 36, 42, 57, 68, 12, 26, 26, 38] The result is : {36: [1], 68: [4], 38: [8], 42: [2], 12: [5], 81: [0], 57: [3], 26: [6, ... Read More

When it is required to convert a list to a customized overlapping nested list, an iteration along with the ‘append’ method can be used.ExampleBelow is a demonstration of the samemy_list = [31, 25, 36, 76, 73, 89, 91, 100] print("The list is :") print(my_list) my_step, my_size = 3, 4 my_result = [] for index in range(0, len(my_list), my_step): my_result.append(my_list[index: index + my_size]) print("The result is :") print(my_result)OutputThe list is : [31, 25, 36, 76, 73, 89, 91, 100] The result is : [[31, 25, 36, 76], [76, 73, 89, 91], [91, 100]]ExplanationA list ... Read More

When it is required to get indices of sign change in a list, a simple iteration along with ‘append’ method can be used.ExampleBelow is a demonstration of the samemy_list = [71, 24, -34, -25, -76, 87, 29, -60, 70, 8] print("The list is :") print(my_list) my_result = [] for index in range(0, len(my_list) - 1):    if my_list[index] > 0 and my_list[index + 1] < 0 or my_list[index] < 0 and my_list[index + 1] < 0:       my_result.append(index) print("The result is :") print(my_result)OutputThe list is : [71, 24, -34, -25, -76, 87, 29, -60, ... Read More