Programming Articles

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Maximum Sum of Two Non-Overlapping Subarrays in C++

Arnab Chakraborty
Arnab Chakraborty
Updated on 13-Nov-2020 302 Views

Suppose we have an array A of integers; we have to find the maximum sum of elements in two non−overlapping subarrays. The lengths of these subarrays are L and M.So more precisely we can say that, we have to find the largest V for whichV = (A[i] + A[i+1] + ... + A[i+L-1]) + (A[j] + A[j+1] + ... + A[j+M-1]) and either −0 = 0, decrease i by 1, decrease j by 1, do −rightL[i + 1] := max of temp and x where x is 0 if i + 2 >= n otherwise x = rightL[i + 2]temp ...

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How to select subsets of data In SQL Query Style in Pandas?

Kiran P
Kiran P
Updated on 10-Nov-2020 435 Views

IntroductionIn this post, I will show you how to perform Data Analysis with SQL style filtering with Pandas. Most of the corporate company’s data are stored in databases that require SQL to retrieve and manipulate it. For instance, there are companies like Oracle, IBM, Microsoft having their own databases with their own SQL implementations.Data scientists have to deal with SQL at some stage of their career as the data is not always stored in CSV files. I personally prefer to use Oracle, as the majority of my company’s data is stored in Oracle.Scenario – 1 Suppose we are given a ...

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How to find the distance among matrix values in R?

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 07-Nov-2020 210 Views

Finding the distance among matrix values means that we want to find the distance matrix and it can be directly found by using dist function with the matrix name. For example, suppose we have a matrix of size 5x5 named as M then the distance matrix can be calculated as dist(M).Example1M1

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How to plot the X-axis labels on the upper-side of the plot in R?

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 07-Nov-2020 1K+ Views

By default, the X−axis labels are plotted on the bottom−axis of the plot and that is referred to as the first axis of axis 1, the second axis is the axis on the left−side, the third axis is the axis on the upper side of the plot, and the fourth axis is on the right−side of the plot. If we want to plot the X−axis labels on the upper−side of the plot then we can use xaxt="n" inside the plot function then define axis for upper−side using axis(3) with semi−colon.Example1x

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How to add a data frame inside a list in R?

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 07-Nov-2020 3K+ Views

A list may contain many objects such as vector, matrix, data frame, list etc. In this way, we can have access to all the necessary objects at the same time. If we want to add a data frame inside a list then we can use the length of the list. For example, if we have a list defined as List and we want to add a data frame df to the List then it can be added as follows −List[[length(List)+1]]

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How to create polynomial regression model in R?

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 07-Nov-2020 1K+ Views

A Polynomial regression model is the type of model in which the dependent variable does not have linear relationship with the independent variables rather they have nth degree relationship. For example, a dependent variable x can depend on an independent variable y-square. There are two ways to create a polynomial regression in R, first one is using polym function and second one is using I() function.Example1set.seed(322) x1

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How to change the thickness of the borders of bars in bar plot created by using ggplot2 in R?

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 07-Nov-2020 4K+ Views

The border thickness highlights the bars and this could be useful in situations where we have similar frequencies. If we want to change the thickness of the bars then size argument under geom_bar function of ggplot2 package can be used and it can be set according to our need starting from 1.ExampleConsider the below data frame −x

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How to create geometric progression series in R?

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 07-Nov-2020 2K+ Views

A geometric progression series is a sequence of numbers in which all the numbers after the first can be found by multiplying the previous one by a fixed number. To generate a geometric progression series in R, we can use seq function. For example, to generate a geometric progression series of 2 by having the difference of multiplication value equal to 1 up to 5 can be found as 2^seq(0, 5, by=1) and the output would be 1, 2, 4, 8, 16, 32.Examples2^seq(0, 5, by=1) [1] 1 2 4 8 16 32 2^seq(0, 5, by=2) [1] 1 4 16 2^seq(0, ...

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How to combine two columns of a data.table object in R?

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 07-Nov-2020 3K+ Views

A data.table object is almost same as a data frame. To combine two columns of a data.table object, we can use paste0 function. For example, if we have a data frame defined as DT that contains two columns named as x and y then we can combine them using the below command.DT[, xy:=paste0(x, y)]ExampleLoading data.table package.> library(data.table)Consider the below data.table object.Example> x y dt1 dt1Outputx y 1: 1 a 2: 2 b 3: 3 c 4: 4 d 5: 5 e 6: 6 f 7: 7 g 8: 8 h 9: 9 i 10: 10 j 11: 11 k 12: ...

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How to extract a data.table row as a vector in R?

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 07-Nov-2020 2K+ Views

A data.table object is similar to a data frame object but there are few things that can be specifically applied to a data.table because data.table package functions was defined for a data.table object only. If we want to extract a data.table row as a vector then we can use as.vector function along with as.matrix so that the as.vector can read the row properly.Loading data.table package:> library(data.table)Consider the below vectors and create a data.table object:Example> x1 x2 x3 x4 x5 DT1 DT1Outputx1 x2 x3 x4 x5 1: B C C D E 2: B C D B E 3: B C ...

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