Commands to Start with

all created variables will be labeled here as “object” but can also just type in datasetName$variableName Thank you to Coursera's Data Analysis class for this info

dim(object)  #shows how many rows, columns, and perhaps series?

## Error: object 'object' not found

# also helps to show if the full file loaded in correctly

names(object)

## Error: object 'object' not found

head(object)  #I'm not sure how these two are different

## Error: object 'object' not found

# head gives a few rows of data in addition to column names

nrow(object)

## Error: object 'object' not found

quantile(object)

## Error: object 'object' not found

# basically shows the range of the data but tells 25%, 50%, and 75% also

summary(object)

## Error: object 'object' not found

# shows qualitative and quant

class(object)  #tells data.frame, but each column can be detected from first row

## Error: object 'object' not found

sapply(object[1, ], class)  #this tells numeric, string, float class etc.

## Error: object 'object' not found

# are variables loaded the way I expected?

unique(dataset$variable)

## Error: object 'dataset' not found

length(unique(dataset$variable))  #tells how many unique items are in that column

## Error: object 'dataset' not found

table(unique(dataset$variable))  #does a count of qual instances

## Error: object 'dataset' not found

table(unique(dataset$variable), dataset$var2)  #does a count of each cell

## Error: object 'dataset' not found

dataset$variable[1:10]  #shows me the first 10 values in that column

## Error: object 'dataset' not found

# great for missing data or searching for charactaristics
any(dataset$variable[1:10] > 40)  #get true or false for each value

## Error: object 'dataset' not found

all(dataset$variable[1:10] < 40)  #get true or false for whole set

## Error: object 'dataset' not found

# & is 'and' | is 'or'

is.na(dataset$variable)

## Error: object 'dataset' not found

sum(is.na(dataset$variable))  #counts the number of times TRUE that na is there shows up.

## Error: object 'dataset' not found

table(is.na(dataset$variable))  #shows how many values are missing and not missing

## Error: object 'dataset' not found

colSums(object)  #if any NA values, the output will be NA

## Error: object 'object' not found

rowSums(object)

## Error: object 'object' not found

rowMeans(variable)

## Error: object 'variable' not found

colMeans(variable, na.rm = TRUE)  #takes out NA values and finishes computing

## Error: object 'variable' not found

# DATA MUNGING label munging in its own R-script is a good idea

# fixing vector characters
tolower(names(datasetName))  #changes the column name of the dataset to all lower case letters

## Error: object 'datasetName' not found

strsplit(names(dataset), "\\.")  #example case. \\escapes the special character . so that

## Error: object 'dataset' not found

toupper(variable)

## Error: object 'variable' not found

sub("_", "", names(dataset), )  #this example replaces the underscore character in the header names with a nothing character basically merging the two sides. BUT only replaces the first instance of the underscore!

## Error: object 'dataset' not found

gsub

## function (pattern, replacement, x, ignore.case = FALSE, perl = FALSE, 
##     fixed = FALSE, useBytes = FALSE) 
## {
##     if (!is.character(x)) 
##         x <- as.character(x)
##     .Internal(gsub(as.character(pattern), as.character(replacement), 
##         x, ignore.case, perl, fixed, useBytes))
## }
## <bytecode: 0x1009c2878>
## <environment: namespace:base>

You can also embed plots, for example:

plot(object)

## Error: object 'object' not found