Table and list helper commands

stdlib-candidate/std-rfc/conversions/into.nu

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+# Convert a Nushell value to a list
+# 
+# Primary useful for range-to-list,
+# but other types are accepted as well.
+# 
+# Example:
+#
+# 1..10 | into list
+export def "into list" []: any -> list {
+  let input = $in
+  let type = ($input | describe --detailed | get type)
+  match $type {
+    range => {$input | each {||}}
+    list => $input
+    table => $input
+    _ => [ $input ]
+  }
+}

stdlib-candidate/std-rfc/tables/col-indices.nu

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+use ../conversions/into.nu *
+use ./select-ranges.nu *
+
+export def main [ ...ranges ] {
+  columns
+  | select ranges $ranges 
+  | get item
+}

stdlib-candidate/std-rfc/tables/mod.nu

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+export use ./select-ranges.nu *
+export use ./reject-ranges.nu *
+export use ./select-column-ranges.nu *
+export use ./reject-column-ranges.nu *
+export use ./row-indices.nu *
+export use ./col-indices.nu *

stdlib-candidate/std-rfc/tables/reject-column-ranges.nu

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+use ./col-indices.nu *
+
+# Relect a range of columns by their indices
+#
+# Example:
+# 
+# ls | reject column-ranges 0 4 5 | first 3
+export def "reject column-ranges" [
+    ...ranges
+] {
+    let column_selector = ($in | col-indices ...$ranges)
+    $in | reject ...$column_selector
+}

stdlib-candidate/std-rfc/tables/reject-ranges.nu

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+use ./row-indices.nu *
+
+# Rejects one or more rows while keeping
+# the original indices.
+#
+# Example - Rejects the first, fifth, and
+# sixth rows from the table:
+#
+# ls / | reject ranges 0 4..5
+export def "reject ranges" [ ...ranges ] {
+  enumerate
+  | flatten
+  | reject ...(row-indices ...$ranges)
+}

stdlib-candidate/std-rfc/tables/row-indices.nu

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+use ../conversions/into.nu *
+
+# Return a list of indices
+# for the provided ranges or indices.
+# Primarily used as a helper for
+# "select ranges" et. al.
+#
+# Example:
+#
+# row-indices 0 2..5 7..8
+# # => ╭───┬───╮
+# # => │ 0 │ 0 │
+# # => │ 1 │ 2 │
+# # => │ 2 │ 3 │
+# # => │ 3 │ 4 │
+# # => │ 4 │ 5 │
+# # => │ 5 │ 7 │
+# # => │ 6 │ 8 │
+# # => ╰───┴───╯
+export def main [ ...ranges ] {
+  $ranges
+  | reduce -f [] {|range,indices|
+    $indices ++ ($range | into list)
+  }
+}

stdlib-candidate/std-rfc/tables/select-column-ranges.nu

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+use ./col-indices.nu *
+
+# Select a range of columns by their indices
+#
+# Example:
+# 
+# ls | select column-ranges 0 4 5 | first 3
+# # => ╭───┬────────────────────╮
+# # => │ # │        name        │
+# # => ├───┼────────────────────┤
+# # => │ 0 │ CITATION.cff       │
+# # => │ 1 │ CODE_OF_CONDUCT.md │
+# # => │ 2 │ CONTRIBUTING.md    │
+# # => ╰───┴────────────────────╯
+export def "select column-ranges" [
+    ...ranges
+] {
+    let column_selector = ($in | col-indices ...$ranges)
+    $in | select ...$column_selector
+}

stdlib-candidate/std-rfc/tables/select-ranges.nu

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+use ./row-indices.nu *
+
+# Selects one or more rows while keeping
+# the original indices.
+#
+# Example - Selects the first, fifth, and
+# sixth rows from the table:
+#
+# ls / | select ranges 0 4..5
+#
+# Example - Select the 5th row:
+#
+# ls / | select 5
+#
+# Example - Select the 4th row.
+# Note that the difference beteen this
+# and `select 3` is that the index (#)
+# column shows the *original* (pre-select)
+# position in the table.
+#
+# ls | select ranges 3
+export def "select ranges" [ ...ranges ] {
+  enumerate
+  | flatten
+  | select ...(row-indices ...$ranges)
+}