Creative
PromptBeginner5 minmarkdown
- `tryCatch(expr
warning = function(w) {...})` catches the **first** warning and exits. Use `withCallingHandlers` + `invokeRestart(muffleWarning)` to suppress warnings but continue.
0
Explore
Find agent skills by outcome
126,408 skills indexed with the new KISS metadata standard.
Showing 24 of 126,408Categories: Creative, Communication, Coding & Debugging, Data, General
General
PromptBeginner5 minmarkdown
- Tests **near equality** with tolerance (default `1.5e-8`
i.e.
0
General
PromptBeginner5 minmarkdown
- Custom conditions: `stop(errorCondition(msg
class = myError))` then catch with `tryCatch(...
0
General
PromptBeginner5 minmarkdown
- `lengths(x)` returns the length of **each element** of a list. Equivalent to `sapply(x
length)` but faster (implemented in C).
0
General
PromptBeginner5 minmarkdown
- `tryCatch(expr
error = function(e) e)` returns the error condition object.
0
General
PromptBeginner5 minmarkdown
- `tryCatch` **unwinds** the call stack — handler runs in the calling environment
not where the error occurred. Cannot resume execution.
0
General
PromptBeginner5 minmarkdown
- `Position(f
x)` returns the **index** of the first match (like `Find` but returns position
0
General
PromptBeginner5 minmarkdown
- `Find(f
x)` returns the **first** element where `f(elem)` is `TRUE`. `Find(f
0
General
PromptBeginner5 minmarkdown
- `Map(f
...)` is a simple wrapper for `mapply(f
0
Creative
PromptBeginner5 minmarkdown
- `Reduce` with `init` adds a starting value: `Reduce(f
x
0
General
PromptBeginner5 minmarkdown
- `Filter(f
x)` keeps elements where `f(elem)` is `TRUE`. Unlike `x[sapply(x
0
General
PromptBeginner5 minmarkdown
- `Reduce(f
x
0
General
PromptBeginner5 minmarkdown
- `Reduce(f
x
0
General
PromptBeginner5 minmarkdown
- `Reduce(f
x)` applies binary function `f` cumulatively: `Reduce(+
0
Data
PromptBeginner5 minmarkdown
- Useful pattern: `do.call(rbind
list_of_dfs)` to combine a list of data frames.
0
General
PromptBeginner5 minmarkdown
- `do.call(fun
args_list)` — `args` must be a **list**
0
General
PromptBeginner5 minmarkdown
- `with(df
expr)` avoids repeating `df$` everywhere
0
General
PromptBeginner5 minmarkdown
> Non-obvious behaviors
gotchas
0
General
PromptBeginner5 minmarkdown
- **misc-utilities.md** — Read when: do.call behaves differently than direct call
need Reduce/Filter/Map
0
General
PromptBeginner5 minmarkdown
- Use `stop()`
`warning()`
0
General
PromptBeginner5 minmarkdown
- **dates-and-system.md** — Read when: Date/POSIXct conversion gives wrong day
time zones cause off-by-one
0
Data
PromptBeginner5 minmarkdown
- **io-and-text.md** — Read when: read.table silently drops data or misparses columns
regex behaves differently than expected
0
Data
PromptBeginner5 minmarkdown
- **visualization.md** — Read when: par settings reset unexpectedly
layout/mfrow interaction is confusing
0
Data
PromptBeginner5 minmarkdown
- **statistics.md** — Read when: hypothesis test gives surprising result
need to choose correct p.adjust method
0