pip_replace: Replace a step

In pipeflow: Fast Interactive Data Analysis Pipelines

Replace a step

Description

Replaces a step's function while keeping it in the same position in the pipeline. Downstream steps that have run before are automatically marked as outdated and will re-run on the next pip_run().

Usage

pip_replace(x, step, fun, tags = NULL, params = list(), exec = NULL)

Arguments

x	A pipeflow pipeline or view object.
step	Unique step name.
fun	Function to execute for the step. Each function parameter must have a default value. Default values that are simple constants are resolved immediately. Default values that are formulas like ~other_step are treated as dependencies to those steps and resolved to the respective output values at runtime once the step is executed. A reference wrapped in try(), like ~try(other_step), accepts a failed input when the pipeline is run with on_error = "continue": instead of the output of the referenced step, the argument then receives a condition of class pipeflow_failure (see section 'Continuing after errors' in pip_run()). The function can refer to the running pipeline as .self (see section 'The pipeline as .self' in pip_add()).
tags	Optional character vector of tags belonging to the step. If NULL (the default), the current tags of the step are kept. Use character(0) to remove all tags.
params	Optional named list of parameter values, which will be merged with the defaults of fun (if overlapping names, the default values in fun take precedence). There are two use cases for params: Provide param values programmatically when adding steps at runtime Provide extra param values to "mark" dependencies that are defined in pipelines nested in a step, which ensures that the step (and with that the pipeline in the step) is re-executed when one of the respective param values change.
exec	Execution mode for the step, see pip_add(). If NULL (the default), the current execution mode of the step is kept.

Details

By default, the step keeps its tags and execution mode: tags = NULL and exec = NULL mean "keep the current value". To change them, pass explicit values, where tags = character(0) removes all tags and exec = "auto" resets the execution mode to its default. Parameters, output, state and lock status are always reset, like for a freshly added step.

Value

The updated pipeline, invisibly.

Examples

p <- pip_new() |>
    pip_add("load", \(n = 5) seq_len(n)) |>
    pip_add("double", \(x = ~load) x * 2)
pip_run(p)
p

# Replace "load" — downstream steps are automatically marked "outdated"
pip_replace(p, "load", \(n = 3) seq_len(n))
p

# Re-run to bring everything up to date
pip_run(p)
p

# If a view is passed, the step must be part of the view
v <- pip_view(p, step = "double")
pip_replace(v, "double", \(x = ~load) x * 3)
p[["state"]]                                # "double" is "new" again

try(pip_replace(v, "load", \(n = 2) seq_len(n)))

# Tags and execution mode are kept unless set explicitly
pip_tag(p, "io")
pip_replace(p, "load", \(n = 4) seq_len(n))
p[, "tags"]
pip_replace(p, "load", \(n = 4) seq_len(n), tags = character(0))
p[, "tags"]

pipeflow documentation built on Oct. 13, 2026, 5:06 p.m.