Util Functionsgetwd() | gets the working directory | setwd("C:/file/path") | sets the working directory | data = read.csv(file.choose()) | opens file explorer to get data | ls() | lists the variables | str(var) | structure of the variable | rm(var) | removes the variable | help.start() | opens help | install.packages("package name") | installs the package | library("package name") | makes the contents available to use | detach("package name") | detaches the package |
StringstoString(x) | helper function to produce a single character string | toupper()/tolower() | converts text to upper/lower case | substring(chr,n,n) | retrieve or replaces the substring of the charachter | paste (…, sep = " ", collapse = NULL) | Concatenate vectors after converting to character |
Arrays and Matrix1D = array(1:24) | 1 dimensional array | 2D = array(1:24, dim = c(6,4)) | 2 dimensional array | 3D = array(1:24, dim = c(4,3,2)) | 3 dimensional array | mat = matrix(1:12, nrow=4, ncol=3) | matrix | cbind(mat1,mat2) | column bind | rbind(mat1,mat2) | row bind |
| | Vectornum = c(1,2,3,4,5,6) | numeric vector | chr = c("aaa","bbb") | character vector | log = c(TRUE,TRUE,FALSE) | logical vector | mean(vec) | mean | sd(vec) | standard deviation | var(vec) | variance | range(vec) | range | which.min(vec)/which.max(vec) | position of the min/max value | rep(1:5,times=3) | replicate elements of vector |
DataFramedf = data.frame(subjectID=1:5,gender=c("M","F","M","M","F"),score=c(8,3,6,5,5)) | dataframe | view(df) | opens editor | head(df)/tail(df) | displays top/bottom n rows | summary(df) | returns descriptive statistics of data |
Descriptive StatisticsrowMeans(data[]) | row mean | rowSums(data[]) | row sum | colMeans(data[]) | column mean | colSums(data[]) | column sum |
Loopsfor (variable in sequence){ Do something } | for loop | while (condition){ Do something } | while loop | if (condition){ Do something } else { Do something different } | ifelse statement |
| | Hypothesist.test(data) | 1 sample t test | t.test(data1,data2) | 2 sample t test | t.test(pre,post,paired=TRUE) | paired sample t test | wilcox.test(data) | Wilcox test | cor.test(data1,data2) | correlation test | chisq.test(data) | Chi square test | shapiro.test(data) | Shapiro test | aov() | ANOVA |
Visualizationqplot(data, line=TRUE,...) | produces quantile-quantile plot | ggplot(data = NULL, mapping = aes(), ...) | initializes a ggplot object | geom_bar() | bar graph | coord_flip() | flip x and y coordinates | facet_grid() | lay out panels in a grid | geom_density | density plot | geom_hist | histogram | geom_point | scatter plots |
Probabilityrbinom(n, size, prob) | Binomial distribution | rpois(n,size) | Poisson distribution | runif(n, min = 0, max = 1) | Uniform distribution | rnorm(n,mean,sd) | Normal distribution | rexp(n) | Exponential distribution |
Statisticssummary(lm(y ~ x1 + x2 + x3, data=mydata)) | multiple regression | summary(glm(y ~ x1 + x2 + x3, family="", data=mydata)) | classification | cluster = kmeans(data) | kmeans cluster analysis |
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