R - Data first glimpse

 

Quick first look

head()
tail()
class()
dim()
names()
str()
glimpse(), from dplyr, like str
summary()

Quick plot

hist(x)
plot(x,y)
boxplot(x, horizontal = TRUE)

Tidy

  • gather(df,key,value, …) key = name of new cat column, value = name of value column, … column to gather or to not gather
  • spread(df, key, value) key = name of new cat column, value = name of value column
  • separate(df, col, into) col = name of 1 column to separate, into = c(names of new columns), sep = ‘-‘
  • unite(df, col, …) col = name of new united column, … = columns to unite, sep = ‘-‘

Clean

lubridate: ymd, ymd_hms etc.

text: tolower(), toupper()

2018-09-11 23_39_32-CleaningData_Chapter_3.pdf - Adobe Acrobat Pro

NA values: complete.cases(df) – find rows without NA, na.omit(df) – only select rows without NA

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