61
votes
30
answers
1.4K
views
Is floating point math broken?
Consider the following code: 0.1 + 0.2 == 0.3 -> false 0.1 + 0.2 -> 0.30000000000000004
59
votes
13
answers
1.9K
views
How to change legend title in ggplot
I have the following plot like below. It was created with this command: library(ggplot2) df <- data.fram
54
votes
4
answers
2.4K
views
Is there an R function for finding the index of an element in a vector?
In R, I have an element x and a vector v. I want to find the first index of an element in v that is equal to x
54
votes
6
answers
2.5K
views
How to find the length of a string in R
How to find the length of a string (number of characters in a string) without splitting it in R? I know how to
52
votes
18
answers
1.5K
views
Convert data.frame columns from factors to characters
I have a data frame. Let's call him bob: > head(bob) phenotype
60
votes
15
answers
1.8K
views
How can I trim leading and trailing white space?
I am having some troubles with leading and trailing white space in a data.frame. For example, I like to take a
62
votes
11
answers
3.1K
views
Sample random rows in dataframe
I am struggling to find the appropriate function that would return a specified number of rows picked up random
52
votes
2
answers
1.9K
views
How to set limits for axes in ggplot2 R plots?
I plot the following: library(ggplot2) carrots <- data.frame(length = rnorm(500000, 10000, 10000)) cu
57
votes
13
answers
1.9K
views
Side-by-side plots with ggplot2
I would like to place two plots side by side using the ggplot2 package, i.e. do the equivalent of par(mfrow=c(
53
votes
13
answers
1.7K
views
Write lines of text to a file in R
In the R scripting language, how do I write lines of text, e.g. the following two lines Hello World to a fi
57
votes
20
answers
2.7K
views
How to rename a single column in a data.frame?
I know if I have a data frame with more than 1 column, I can use colnames(x) <- c("col1","col2") to ren
64
votes
29
answers
2.6K
views
Elegant way to check for missing packages and install them?
I seem to be sharing a lot of code with coauthors these days. Many of them are novice/intermediate R users and
56
votes
8
answers
921
views
How to add leading zeros?
I have a set of data which looks something like this: anim <- c(25499,25500,25501,25502,25503,25504) sex
65
votes
9
answers
1.6K
views
Combine a list of data frames into one data frame by row
I have code that at one place ends up with a list of data frames which I really want to convert to a single bi
54
votes
12
answers
1.9K
views
How can two strings be concatenated?
How can I concatenate (merge, combine) two values? For example I have: tmp = cbind("GAD", "AB") tmp # [,
57
votes
2
answers
2.5K
views
Why is `[` better than `subset`?
When I need to filter a data.frame, i.e., extract rows that meet certain conditions, I prefer to use the subse
61
votes
6
answers
1.9K
views
How do I install an R package from source?
A friend sent me along this great tutorial on webscraping NYtimes with R. I would really love to try it. Howev
53
votes
10
answers
1.8K
views
Extracting specific columns from a data frame
I have an R data frame with 6 columns, and I want to create a new dataframe that only has three of the columns
52
votes
5
answers
2.7K
views
How to write trycatch in R
I want to write trycatch code to deal with error in downloading from the web. url <- c( "http://stat.e
57
votes
15
answers
1.5K
views
How to sum a variable by group
I have a data frame with two columns. First column contains categories such as "First", "Second", "Third", and