missing lazy functions

[sorhawell]

the following functions py-polars/polars/functions/lazy.py are not yet translated in ./R/functions__lazy.R (file renamed in #196).

tag any merged translated, or write your name after to reserve it for a PR

• pl$map
• pl$apply
• pl$fold (Implement reduce() and fold() #403)
• pl$reduce (Implement reduce() and fold() #403)
• pl$cum_fold
• pl$cum_reduce
• pl$exclude
• pl$groups (maybe wait for Deprecate Expr.agg_groups() and refactor pl.groups(column_name) to pl.groups() polars#13274)
• pl$format
• pl$cumsum
• pl$any
• pl$all cover bitwise also
• pl$quantile
• pl$arange
• pl$collect_all => @etiennebacher: I don't think we need to implement this, it's basically lapply(<list of LF>, \(x) x$collect())
• pl$repeat
• pl$arg_where
• pl$spearman_rank_corr --- Deprecated in pypolars
• pl$pearson_corr --- Deprecated in pypolars
• pl$corr (Implement cov, corr, rolling_cov, rolling_corr #351)
• pl$cov (Implement cov, corr, rolling_cov, rolling_corr #351)
• pl$arg_sort_by
• pl$duration
• pl$datetime_
• pl$date_
• pl$concat_str_ (Implement concat_str() #349)
• pl$from_epoch (Implement pl$from_epoch() #708)
• pl$rolling_cov (Implement cov, corr, rolling_cov, rolling_corr #351)
• pl$rolling_corr (Implement cov, corr, rolling_cov, rolling_corr #351)