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Articles by Nizamuddin Siddiqui
Page 40 of 196
How to remove first character from column name in R data frame?
To remove first character from column name in R data frame, we can use str_sub function of stringr package.For Example, if we have a data frame called df that contains two columns say XID and XDV then we can remove X from both the column names by using the below mentioned command −names(df)=str_sub(names(df),2)Example 1Following snippet creates a sample data frame −XColor
Read MoreHow to increase the width of the X-axis line for a ggplot2 graph?
To increase the width of the X-axis line for a ggplot2 graph in R, we can use theme function where we can set the axis.line.x.bottom argument size to desired size with element_line.Check out the below Example to understand how it can be done.ExampleFollowing snippet creates a sample data frame −x
Read MoreChange the color of X-axis line for a graph using ggplot2.
To change the color of X-axis line for a graph using ggplot2, we can use theme function where we can set the axis.line.x.bottom argument color to desired color with element_line.Check out the below Example to understand how it can be done. This might be required when we want to highlight the X-axis for viewers.ExampleFollowing snippet creates a sample data frame −x
Read MoreHow to find the row wise mode of strings in an R data frame?
To find the row wise model of strings in an R data frame, we can use apply function along with custom function for mode, if ties will be there then first value will be chosen based on alphabetical ordering.For Example, if we have a data frame called df that contains string values then we can find the row wise mode of strings by using the command given below −df$RowM
Read MoreHow to deal with error 'height' must be a vector or a matrix while creating barplot?
The error 'height' must be a vector or a matrix while creating barplot occurs when we provide data frame name instead of column names or read it with as.matrix. If we want to create bar plot for columns in a data frame then the data frame needs to be read as matrix.For Example, if we have a data frame called df then we can create the barplot of columns in df by using the command given below −barplot(as.matrix(df))ExampleFollowing snippet creates a sample data frame −df
Read MoreHow to find bootstrap confidence interval in R?
The bootstrap confidence interval can be found by using the boot function. The bootstrapping is a method of finding inferential statistics with the help of sample data. It is done by drawing a large number of samples with replacement from the same values. Check out the Examples given below to understand how we can create a bootstrap confidence interval.Example 1Following snippet creates a sample data frame −x1
Read MoreHow to find the frequency based on intervals in R data frame?
To create intervals, we can use cut function with seq function and if we want to find the frequency based on these intervals then we just need to use table function along with cut function. We need to properly define the values for interval inside cut function. To understand how it can be done, check out the below Examples.Example 1Following snippet creates a sample data frame −x
Read MoreFind the unique pair combinations of an R data frame column values.
To find the unique pair combinations of an R data frame column values, we can use combn function along with unique function.For Example, if we have a data frame called df that contains a column say x then we can find the unique pair combinations of all column values by using the command given below −combn(unique(df$x),2,FUN=paste,collapse=' ')Example 1Following snippet creates a sample data frame −Grp
Read MoreCreate a random sample by ignoring missing values in an R vector.
To create a random sample by ignoring missing values in an R vector, we can use sample function and the negation of is.na with vector name.For Example, if we have a vector called X that contains some NAs then we can create a random sample of size 100 of X values by using the command given below −sample(X[!is.na(X)],100,replace=TRUE)Example 1To create a random sample by ignoring the missing values in an R vector, use the command given below −x1
Read MoreHow to check which value is NA in an R data frame?
To check which value in NA in an R data frame, we can use apply function along with is.na function.For Example, if we have a data frame called df that contains some NA values then we can check which value is NA by using the command mentioned below −apply(df,2, function(x) is.na(x))This will return the data frame in logical form with TRUE and FALSE. Check out the below Examples to understand how it works.Example 1Following snippet creates a sample data frame −x1
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