Coming from dplR¶

dplPy is a Python companion to the R library dplR, and most workflows translate almost one-to-one. The biggest differences are ergonomic rather than conceptual:

Data structure. dplR uses a data.frame of class "rwl" (years as row names); dplPy uses a pandas DataFrame indexed by year. Same idea, same orientation (years down, series across).
Naming. R's dotted names become Python underscores (read.crn → read_crn, chron.ars → chron_ars).
Calling style. library(dplR); chron(rwi) becomes import dplpy as dpl; dpl.chron(rwi).
Return values. Some functions that print in R return a dict or DataFrame in dplPy (for example xdate returns a dict of segment correlations and flags).

Function map¶

Reading & writing¶

dplR	dplPy	Notes
`read.rwl`, `read.tucson`, `read.compact`	`readers`	Auto-detects format; `readers_url` for URLs
`read.crn`	`read_crn`	Single, stacked, and combined multi-site files
`read.ids`	`read_ids`	Site–tree–core parsing
`write.rwl` / `write.tucson`	`writers(..., format="rwl")`
`write.crn`	`writers(..., format="crn")`
`combine.rwl`	`combine_rwl`

Descriptive statistics¶

dplR	dplPy	Notes
`rwl.stats`	`stats`	Per-series mean, stdev, skew, kurtosis, gini, AR1, …
`rwl.report`	`report`
`summary`	`summary`
`sens1`, `sens2`	`sens1`, `sens2`	Mean sensitivity (kept out of `stats`, as in dplR)
`gini.coef`	(column in `stats`)	Reported in the `stats` table

Detrending & standardization¶

dplR	dplPy	Notes
`detrend`, `detrend.series`	`detrend`	`fit=` selects Spline / ModNegExp / ModHugershoff / Mean / AgeDepSpline
`rcs`	`rcs`	`preset="crust"` for the CRUST regional curve
`ssf`	`ssf`	Signal-free; `preset="crust"` variant
`ads` (age-dependent spline)	`ads`	Also `detrend(fit="AgeDepSpline")`
`powt`	`powt`	Power transformation

Chronology¶

dplR	dplPy	Notes
`chron`	`chron`	`prewhiten=True` adds the residual chronology
`chron.ars`	`chron_ars`	ARSTAN-style
`chron.stabilized`	`chron_stabilized`	Variance stabilization
`ar` / AR modelling	`autoreg`, `ar_func`	Yule-Walker by default, matching R's `ar()`

Crossdating¶

dplR	dplPy	Notes
`corr.rwl.seg`	`xdate`	dplR-faithful default; returns a dict
`corr.series.seg`	`series_corr`	Single-series diagnostics
`ccf.series.rwl`	`series_corr`	Cross-correlation view of one series
`interseries.cor`	`interseries_corr`	Overall interseries correlation
`xdate.floater`	`xdate_floater`	Extended with Wilson (2026) t-statistics
(COFECHA has no dplR equivalent)	`xdate(preset="COFECHA")`, `xdate_report`	COFECHA emulation and batch report

Signal strength, agreement & indices¶

dplR	dplPy	Notes
`rwi.stats`, `rwi.stats.running`	`rwi_stats`, `rwi_stats_running`
`sss`	`sss`	Subsample signal strength
`glk`, `sgc`	`glk`, `sgc`	Gleichläufigkeit / synchronous growth changes
`treeMean`	`tree_mean`	Average cores to tree level
`common.interval`	`common_interval`
`bai.out`, `bai.in`	`bai_out`, `bai_in`	Basal area increment
`po.to.wc`, `wc.to.po`	`po_to_wc`, `wc_to_po`	Pith-offset conversion
`fill.internal.NA`	`fill_internal`	Interior-gap infilling

Plotting¶

dplR	dplPy	Notes
`plot.rwl`, `plot.crn`, `spag.plot`, `seg.plot`	`plot`	`type=` selects the plot style
crossdating plots	`xdate(make_plot=True)`, `xdate_plot`, `series_corr(make_plot=True)`

Beyond dplR¶

dplPy adds LiPD interchange, which dplR does not provide:

dplPy	Notes
`to_lipd`, `from_lipd`, `lipd_metadata`	Requires the `[lipd]` extra

Not yet ported¶

dplPy targets the core standardization, chronology, and crossdating workflow. Some specialized dplR tools — for example superposed epoch analysis, spectral and wavelet methods, skeleton-plot crossdating, and interactive detrending — are not yet available. Check the API Reference for the current surface, and the project repository to request or contribute a port.

A note on fidelity¶

Where dplPy claims to reproduce a dplR (or COFECHA, or ARSTAN) method, the behavior is checked against those reference implementations, and deliberate departures are documented in the relevant function's docstring. The clearest example is crossdating: xdate's A flag reproduces dplR's corr.rwl.seg exactly, while its B (lag-shift) flag is a documented COFECHA-style addition that dplR does not have.