Vector
- Create
- Get
- Reorder
- Indexing
- Update (element-wise)
- Aggregate
- Shrink
- Convert
Create
| What | How | Details |
| Define vector | c(1, 2, 3) | |
| Zeros, length n | numeric(n) | |
| Zeros, length n | vector('numeric', n) | |
| NaNs, length n | NaN[1:3] | |
| Sequence from a to b | seq(a, b) | |
| Sequence between a to b of length n | seq(a, b, length.out=n) | |
| Repeat vector | rep(x, 2) | |
| Repeat vector up to length n | rep_len(x, n) | |
| Create vector or matrix depending on the columns | mat.or.vec(1:5, nc=2) | |
Get
| What | How | Details |
| Length | length(x) | |
| Element names | names(x) | |
| First element | x[0] | |
| Last element | last(x) | |
Reorder
| What | How | Details |
| Sort descending | sort(x) | |
| Reverse | rev(x) | |
| Shuffle | sample(x) | |
Indexing
| What | How | Details |
TRUE values | which(x) | |
| Largest value | which.max(x) | |
| Smallest value | which.min(x) | |
| Order by value, breaking ties with further args | order(x) | |
| Ranking, with ties option | rank(x, ties='first') | |
Update (element-wise)
| What | How | Details |
| If-else | ifelse(x == TRUE, 1, 0) | |
| If-else with consecutive output | ifelse(x, seq(-1, -100, by=-1), 1:100) | |
| Replace NAs by zeros | ifelse(is.na(x), 0, x) | |
| Replace specific values by zeros | ifelse(x %in% values, 0, x) | |
| Replace elements at index with given values | replace(x, c(2, 4), c(NA, Inf)) | |
| Clip values below a | pmin(x, a) | |
| Clip values above b | pmax(x, b) | |
| Find element-wise min/max values between vectors | pmax(x, y) | |
| Discretize values into bin number | findInterval(1:4, c(0, 2, 4)) | |
| Discretize values into n levels | cut(x, n) | |
| Discretize values in intervals | cut(x, breaks) | |
| Linear interpolation | approxfun(x, method='linear')(x2) | |
| Spline interpolation | splinefun(x)(x2) | |
| Smoothing spline interpolation | smooth.spline(x) %>% predict(x2) | |
Aggregate
| What | How | Details |
| Sum | sum(x) | |
| Mean | mean(x) | |
| Mode | table(x) %>% sort() %>% names() %>% last() | |
Mode of positive integers 1:K | tabulate(x) %>% which.max() | |
| Compute function per group, as list | tapply(x, INDEX = rep_len(1:2, length(x)), mean) | outputs a list with the results per group |
Shrink
| What | How | Details |
| Exclude NA | na.exclude(x) | |
| Exclude NA | x[!is.na(x)] | |
| Exclude NA | Filter(Negate(is.na), x) | |
| Exclude non-finite values | x[is.finite(x)] | |
| Exclude non-finite values | Filter(is.finite, x) | |
| Lagged difference | diff(x) | |
| Sample n elements | sample(x, n) | |
Convert
| What | How | Details |
| Split vector into list of vectors, according to grouping | split(1:10, rep(1:2, 5) | Can be undone by unsplit(x, rep(1:2, 5)) |
| Running-length encoding | rle(x) | |