seq-decimal: Sequence generation at decimal level

Description

Functions that provide a smooth interface to generating sequences based on the input values' decimal depth. Each function creates a sequence with a step size of one unit on the level of the input values' ultimate decimal digit (e.g., 2.45, 2.46, 2.47, ...):

seq_endpoint() creates a sequence from one input value to another. For step size, it goes by the value with more decimal places.
seq_distance() only takes the starting point and, instead of the endpoint, the desired output length. For step size, it goes by the starting point by default.

seq_endpoint_df() and seq_distance_df() are variants that create a data frame. Further columns can be added as in tibble::tibble(). Regular arguments are the same as in the respective non-df function, but with a dot before each.

Usage

seq_endpoint(from, to, offset_from = 0L, offset_to = 0L, string_output = TRUE)
seq_distance(
  from,
  by = NULL,
  length_out = 10L,
  dir = 1,
  offset_from = 0L,
  string_output = TRUE
)
seq_endpoint_df(
  .from,
  .to,
  ...,
  .offset_from = 0L,
  .offset_to = 0L,
  .string_output = TRUE
)
seq_distance_df(
  .from,
  .by = NULL,
  ...,
  .length_out = 10L,
  .dir = 1,
  .offset_from = 0L,
  .string_output = TRUE
)

Value

String by default of string_output, numeric otherwise.

Arguments

from, .from: Numeric (or string coercible to numeric). Starting point of the sequence.
to, .to: Numeric (or string coercible to numeric). Endpoint of the sequence. Only in seq_endpoint() and seq_endpoint_df().
offset_from, .offset_from: Integer. If set to a non-zero number, the starting point will be offset by that many units on the level of the last decimal digit. Default is 0.
offset_to, .offset_to: Integer. If set to a non-zero number, the endpoint will be offset by that many units on the level of the last decimal digit. Default is 0. Only in seq_endpoint() and seq_endpoint_df().
string_output, .string_output: Logical or string. If TRUE (the default), the output is a string vector. Decimal places are then padded with zeros to match from's (or to's) number of decimal places. "auto" works like TRUE if and only if from (.from) is a string.
by, .by: Numeric. Only in seq_distance() and seq_distance_df(). Step size of the sequence. If not set, inferred automatically. Default is NULL.
length_out, .length_out: Integer. Length of the output vector (i.e., the number of its values). Default is 10. Only in seq_distance() and seq_distance_df().
dir, .dir: Integer. If set to -1, the sequence goes backward. Default is 1. Only in seq_distance() and seq_distance_df().
...: Further columns, added as in tibble::tibble(). Only in seq_endpoint_df() and seq_distance_df().

Details

If either from or to ends on zero, be sure to enter that value as a string! This is crucial because trailing zeros get dropped from numeric values. A handy way to format numeric values or number-strings correctly is restore_zeros(). The output of the present functions is like that by default (of string_output).

In seq_endpoint() and seq_endpoint_df(), the step size is determined by from and to, whichever has more decimal places. In seq_distance() and seq_distance_df(), it's determined by the decimal places of from.

These functions are scrutiny's take on base::seq(), and themselves wrappers around it.

Examples

Run this code

# Sequence between two points:
seq_endpoint(from = 4.7, to = 5)

# Sequence of some length; default is 10:
seq_distance(from = 0.93)
seq_distance(from = 0.93, length_out = 5)

# Both of these functions can offset the
# starting point...
seq_endpoint(from = 14.2, to = 15, offset_from = 4)
seq_distance(from = 14.2, offset_from = 4)

# ...but only `seq_endpoint()` can offset the
# endpoint, because of its `to` argument:
seq_endpoint(from = 9.5, to = 10, offset_to = 2)

# In return, `seq_distance()` can reverse its direction:
seq_distance(from = 20.03, dir = -1)

# Both functions have a `_df` variant that returns
# a data frame. Arguments are the same but with a
# dot, and further columns can be added as in
# `tibble::tibble()`:
seq_endpoint_df(.from = 4.7, .to = 5, n = 20)
seq_distance_df(.from = 0.43, .length_out = 5, sd = 0.08)