General
PromptBeginner5 minmarkdownQuality: 24
- `with(df
expr) avoids repeating df$` everywhere
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Showing 24 of 132,656Categories: Data & Insights, Education, Data, Coding & Debugging, General
General
PromptBeginner5 minmarkdownQuality: 28
- misc-utilities.md — Read when: do.call behaves differently than direct call
need Reduce/Filter/Map
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General
PromptBeginner5 minmarkdownQuality: 28
- dates-and-system.md — Read when: Date/POSIXct conversion gives wrong day
time zones cause off-by-one
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Data
PromptBeginner5 minmarkdownQuality: 28
- io-and-text.md — Read when: read.table silently drops data or misparses columns
regex behaves differently than expected
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Data
PromptBeginner5 minmarkdownQuality: 28
- visualization.md — Read when: par settings reset unexpectedly
layout/mfrow interaction is confusing
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Data
PromptBeginner5 minmarkdownQuality: 28
- statistics.md — Read when: hypothesis test gives surprising result
need to choose correct p.adjust method
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Data
PromptBeginner5 minmarkdownQuality: 28
- data-wrangling.md — Read when: subsetting returns wrong type
apply on data frame gives unexpected coercion
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General
PromptBeginner5 minmarkdownQuality: 24
- modeling.md — Read when: formula syntax is confusing (I()
* vs :
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General
PromptBeginner5 minmarkdownQuality: 24
For deeper coverage
read the reference files in references/:
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General
PromptBeginner5 minmarkdownQuality: 24
Non-obvious behaviors
surprising defaults
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General
PromptBeginner5 minmarkdownQuality: 24
labels = c(low
med
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General
PromptBeginner5 minmarkdownQuality: 24
cbind(df1
df2) # bind columns (same rows)
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General
PromptBeginner5 minmarkdownQuality: 24
df$category <- cut(df$value
breaks = c(0
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General
PromptBeginner5 minmarkdownQuality: 24
rbind(df1
df2) # stack rows (same columns)
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General
PromptBeginner5 minmarkdownQuality: 24
df[!duplicated(df$id)
]
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General
PromptBeginner5 minmarkdownQuality: 24
df[!duplicated(df)
]
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General
PromptBeginner5 minmarkdownQuality: 24
df[order(df$group
-df$value)
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General
PromptBeginner5 minmarkdownQuality: 24
varying = list(c(v1
v2))
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General
PromptBeginner5 minmarkdownQuality: 24
df[order(-df$value)
] # descending
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General
PromptBeginner5 minmarkdownQuality: 24
df[order(df$value)
] # ascending
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General
PromptBeginner5 minmarkdownQuality: 24
long <- reshape(wide
direction = long
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General
PromptBeginner5 minmarkdownQuality: 24
idvar = id
timevar = time
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General
PromptBeginner5 minmarkdownQuality: 24
wide <- reshape(long
direction = wide
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General
PromptBeginner5 minmarkdownQuality: 24
merged <- merge(df1
df2
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