Programming Articles - Page 1079 of 3363

ExampleBelow is a demonstration of the samedef diff_summation_elem(row): return sum([abs(row[index + 1] - row[index]) for index in range(0, len(row) - 1)]) my_list = [[97, 6, 47, 3], [6, 88, 3, 26], [71, 53, 34, 65], [15, 36, 5, 62]] print("The list is : ") print(my_list) my_list.sort(key=diff_summation_elem) print("The resultant list is :" ) print(my_list)OutputThe list is : [[97, 6, 47, 3], [6, 88, 3, 26], [71, 53, 34, 65], [15, 36, 5, 62]] The resultant list is : [[71, 53, 34, 65], [15, 36, 5, 62], [97, 6, 47, 3], [6, 88, 3, 26]]ExplanationA ... Read More

When it is required to append given number with every element of the list, a list comprehension is used.ExampleBelow is a demonstration of the samemy_list = [25, 36, 75, 36, 17, 7, 8, 0] print ("The list is :") print(my_list) my_key = 6 my_result = [x + my_key for x in my_list] print ("The resultant list is :") print(my_result)OutputThe list is : [25, 36, 75, 36, 17, 7, 8, 0] The resultant list is : [31, 42, 81, 42, 23, 13, 14, 6]ExplanationA list is defined and is displayed on the console.An integer value for key ... Read More

When it is required to get the cumulative row frequencies in a list, the ‘Counter’ method, and a list comprehension are used.ExampleBelow is a demonstration of the samefrom collections import Counter my_list = [[11, 2, 32, 4, 31], [52, 52, 3, 71, 71, 3], [1, 3], [19, 19, 40, 40, 40]] print("The list is :") print(my_list) my_element_list = [19, 2, 71] my_frequency = [Counter(element) for element in my_list] my_result = [sum([freq[word] for word in my_element_list if word in freq]) for freq in my_frequency] print("The resultant matrix is :") print(my_result)OutputThe list is : [[11, 2, ... Read More

When it is required to get the minimum element to construct a string, the ‘set’ operator, the ‘combinations’ method, the ‘issubset’ method and a simple iteration is required.ExampleBelow is a demonstration of the samefrom itertools import combinations my_list = ["python", "is", "fun", "to", "learn"] print("The list is :") print(my_list) my_target_str = "onis" my_result = -1 my_set_string = set(my_target_str) complete_val = False for value in range(0, len(my_list) + 1): for sub in combinations(my_list, value): temp_set = set(ele for subl in sub for ele in subl) ... Read More

The indexing operator is the square brackets for creating a subset dataframe. Let us first create a Pandas DataFrame. We have 3 columns in the DataFramedataFrame = pd.DataFrame({"Product": ["SmartTV", "ChromeCast", "Speaker", "Earphone"], "Opening_Stock": [300, 700, 1200, 1500], "Closing_Stock": [200, 500, 1000, 900]})Creating a subset with a single columndataFrame[['Product']]Creating a subset with multiple columnsdataFrame[['Opening_Stock', 'Closing_Stock']]ExampleFollowing is the complete codeimport pandas as pd dataFrame = pd.DataFrame({"Product": ["SmartTV", "ChromeCast", "Speaker", "Earphone"], "Opening_Stock": [300, 700, 1200, 1500], "Closing_Stock": [200, 500, 1000, 900]}) print"DataFrame...", dataFrame print"Displaying a subset using indexing operator:", dataFrame[['Product']] print"Displaying a subset with multiple columns:", dataFrame[['Opening_Stock', 'Closing_Stock']]OutputThis will ... Read More

The numpy where() method can be used to filter Pandas DataFrame. Mention the conditions in the where() method. At first, let us import the required libraries with their respective aliasimport pandas as pd import numpy as npWe will now create a Pandas DataFrame with Product records dataFrame = pd.DataFrame({"Product": ["SmartTV", "ChromeCast", "Speaker", "Earphone"], "Opening_Stock": [300, 700, 1200, 1500], "Closing_Stock": [200, 500, 1000, 900]})Use numpy where() to filter DataFrame with 2 ConditionsresValues1 = np.where((dataFrame['Opening_Stock']>=700) & (dataFrame['Closing_Stock']< 1000)) print"Filtered DataFrame Value = ", dataFrame.loc[resValues1] Let us use numpy where() again to filter DataFrame with 3 conditionsresValues2 = np.where((dataFrame['Opening_Stock']>=500) & (dataFrame['Closing_Stock']< 1000) ... Read More

To sum all the rows of a DataFrame, use the sum() function and set the axis value as 1. The value axis 1 will add the row values.At first, let us create a DataFrame. We have Opening and Closing Stock columns in itdataFrame = pd.DataFrame({"Opening_Stock": [300, 700, 1200, 1500], "Closing_Stock": [200, 500, 1000, 900]})Finding sum of row values. Axis is set 1 to add row valuesdataFrame = dataFrame.sum(axis = 1) ExampleFollowing is the complete code import pandas as pd dataFrame = pd.DataFrame({"Opening_Stock": [300, 700, 1200, 1500], "Closing_Stock": [200, 500, 1000, 900]}) print"DataFrame...", dataFrame # finding sum of ... Read More

To delete a row from a DataFrame, use the drop() method and set the index label as the parameter.At first, let us create a DataFrame. We have index label as w, x, y, and z:dataFrame = pd.DataFrame([[10, 15], [20, 25], [30, 35], [40, 45]], index=['w', 'x', 'y', 'z'], columns=['a', 'b'])Now, let us use the index label and delete a row. Here, we will delete a row with index label 'w'.dataFrame = dataFrame.drop('w') ExampleFollowing is the codeimport pandas as pd # Create DataFrame dataFrame = pd.DataFrame([[10, 15], [20, 25], [30, 35], [40, 45]], index=['w', 'x', 'y', 'z'], columns=['a', 'b']) ... Read More

To append rows to a DataFrame, use the append() method. Here, we will create two DataFrames and append one after the another.At first, import the pandas library with an alias −import pandas as pdNow, create the 1st DataFramedataFrame1 = pd.DataFrame(    { "Car": ['BMW', 'Lexus', 'Audi', 'Jaguar'] } )Create the 2nd DataFramedataFrame2 = pd.DataFrame( { "Car": ['Mercedes', 'Tesla', 'Bentley', 'Mustang'] } )Next, append rows to the enddataFrame1 = dataFrame1.append(dataFrame2)ExampleFollowing is the codeimport pandas as pd # Create DataFrame1 dataFrame1 = pd.DataFrame( { "Car": ['BMW', 'Lexus', 'Audi', 'Jaguar'] } ) print"DataFrame1 ...", dataFrame1 # Find ... Read More

To create a subset by choosing specific values from columns based on indexes, use the iloc() method. Let us first import the pandas libraryimport pandas as pdCreate a Pandas DataFrame with Product records. We have 3 columns in itdataFrame = pd.DataFrame({"Product": ["SmartTV", "ChromeCast", "Speaker", "Earphone"], "Opening_Stock": [300, 700, 1200, 1500], "Closing_Stock": [200, 500, 1000, 900]})Creating a subset with 2 columns and 1st 2 rows using iloc(print"Displaying a subset using iloc() = ", dataFrame.iloc[0:2, 0:2] ExampleFollowing is the complete codeimport pandas as pd dataFrame = pd.DataFrame({"Product": ["SmartTV", "ChromeCast", "Speaker", "Earphone"], "Opening_Stock": [300, 700, 1200, 1500], "Closing_Stock": [200, 500, 1000, 900]}) ... Read More