Data
PromptBeginner5 minmarkdown
- **data-wrangling.md** — Read when: subsetting returns wrong type
apply on data frame gives unexpected coercion
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General
PromptBeginner5 minmarkdown
- **modeling.md** — Read when: formula syntax is confusing (`I()`
`*` vs `:`
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General
PromptBeginner5 minmarkdown
Non-obvious behaviors
surprising defaults
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General
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For deeper coverage
read the reference files in `references/`:
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General
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labels = c(low
med
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General
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df$category <- cut(df$value
breaks = c(0
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General
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df[!duplicated(df$id)
]
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General
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cbind(df1
df2) # bind columns (same rows)
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General
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rbind(df1
df2) # stack rows (same columns)
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General
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df[order(df$group
-df$value)
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General
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df[!duplicated(df)
]
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General
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df[order(-df$value)
] # descending
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General
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df[order(df$value)
] # ascending
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General
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varying = list(c(v1
v2))
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General
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long <- reshape(wide
direction = long
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General
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wide <- reshape(long
direction = wide
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General
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merged <- merge(df1
df2
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General
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idvar = id
timevar = time
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General
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cor.test(x
y
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General
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merged <- merge(df1
df2
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General
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merged <- merge(df1
df2
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Data
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fit <- aov(value ~ group
data = df)
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General
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t.test(before
after
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General
PromptBeginner5 minmarkdown
chisq.test(table(df$a
df$b))
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