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While using python for data manipulation, we may come across lists whose elements are a mix of letters and numbers with a fixed pattern. In this article we will see how to separate the numbers form letters which can be used for future calculations.With splitThe split functions splits a string by help of a character that is treated as a separator. In the program below the list elements have hyphen as their separator between letters and text. We will use that along with a for loop to capture eachExample Live DemolistA = ['Mon-2', 'Wed-8', 'Thu-2', 'Fri-7'] # Given list print("Given ... Read More
During data manipulation with Python , we may need to bring two lists together and equate the elements in each of them pair wise. Which means the element at index 0 from list 1 will be equated with element from index 0 of list2 and so on.With tupleThe tuple function will be leveraged to take elements form each list in sequence and matching them up. We first store the result in a temp string which has the pattern in which the output of matching up of the values form lists will be displayed.Example Live DemolistA = ['day1', 'day2', 'day3'] listB = ... Read More
Suppose some people will make friend requests. We know their ages, these are stored in ages[i]. So this indicates that the age of the ith person. Now a A will NOT friend request person B (B != A) if any of the following conditions are true −age[B] age[A]age[B] > 100 && age[A] < 100Otherwise, A will friend request B. You can consider that if A requests B, B does not necessarily request A. And also, people will not friend request themselves. So we have to find how many total friend requests are made?Suppose if the age array is like ... Read More
A lot of statistical data analysis tries to find the values which have maximum frequency in a given list of values. Python provides multiple approaches using which we can find such value form a given list. Below are the approaches.Using CounterThe Counter function from collections module has a options which can directly find the most common element in a given list. We have the most_common function to which we pass a parameter 1 for only one element with highest frequency and pass 2 if we need two elements which have highest frequency.Example Live Demofrom collections import Counter # Given list ... Read More
There are scenarios when we need to repeat the values in a list. This duplication of values can be achived in python in the following ways.Using nested for loopIt is a straight forward approach in which pick each element, take through a inner for loop to create its duplicate and then pass both of them to an outer for loop.Example Live Demo# Given list listA = ['Mon', 'Tue', 9, 3, 3] print("Given list : ", listA) # Adding another element for each element Newlist = [i for i in listA for n in (0, 1)] # Result print("New ... Read More
The elements in tow lists can be involved in a division operation for some data manipulation activity using python. In this article we will see how this can be achieved.With zipThe zip function can pair up the two given lists element wise. The we apply the division mathematical operator to each pair of these elements. Storing the result into a new list.Example Live Demo# Given lists list1 = [12, 4, 0, 24] list2 = [6, 3, 8, -3] # Given lists print("Given list 1 : " + str(list1)) print("Given list 2 : " + str(list2)) # Use zip res ... Read More
Suppose we have a list of positive integers; whose value is greater than 1. We will make a binary tree, using these integers, and each number may be used as many times as we want. Each non-leaf node should be the product of its children. So we have to find how many trees can we make? The answer will be returned in modulo 10^9 + 7. So if the input is like [2, 4, 5, 10], then the answer will be 7, as we can make 7 trees like [2], [4], [5], [10], [4, 2, 2], [10, 2, 5], [10, ... Read More
Suppose on a table are N cards, with a positive integer printed on both side of each card (possibly different). We have to flip any number of cards, and after we choose one card. If the number X on the back side of the chosen card is not on the front of any card, then the number X is known as good. We have to find the smallest number that is good? When no number is good, return 0. Here, fronts[i] and backs[i] represent the number on the front and back side of card i. A flip will swap the ... Read More
Suppose we have a list of words, we may encode it by writing a reference string S and a list of indexes A. So for example, let us consider if the list of words is ["time", "me", "bell"], then we can write it as S = "time#bell#" and indexes = [0, 2, 5]. Here for each index, we will recover the word by reading from the reference string from that index until we reach the "#" symbol.So we have to find what is the length of the shortest reference string S possible that encodes the given words? So for the ... Read More
Suppose we have given a head; this is the head node of a linked list containing unique integer values. Now we are also given the list G, a subset of the values in the linked list. We have to find the number of connected components in G, where two values are connected if they appear consecutively in the linked list. So if the list is like [0, 1, 2, 3] and G = [0, 1, 3], then output will be 2, as 0 and 1 are connected, so there are two lists [0, 1] and [3].To solve this, we will ... Read More