polars selector alpha for expression
Select all columns with alphabetic names (eg: only letters). Matching column names cannot contain *any* non-alphabetic characters. Note that the definition of "alphabetic" consists of all valid Unicode alphabetic characters by default; this can be changed by setting `--ascii-only`.
Signature
> polars selector alpha {flags}
Flags
-
--ascii-only, -a: Indicate whether to consider only ASCII alphabetic characters, or the full Unicode range of valid letters (accented, idiographic, etc). -
--ignore-spaces, -s: Indicate whether to ignore the presence of spaces in column names; if so, only the other (non-space) characters are considered.
Input/output types:
| input | output |
|---|---|
| any | polars_selector |
Examples
Select columns with alphabetic names; note that accented characters and kanji are recognised as alphabetic here.
>
{
"no1": [100, 200, 300],
"café": ["espresso", "latte", "mocha"],
"t or f": [true, false, null],
"hmm": ["aaa", "bbb", "ccc"],
"都市": ["東京", "大阪", "京都"],
} |
polars into-df --as-columns |
polars select (polars selector alpha) |
polars sort-by café hmm 都市 |
polars collect
╭───┬──────────┬─────┬──────╮
│ # │ café │ hmm │ 都市 │
├───┼──────────┼─────┼──────┤
│ 0 │ espresso │ aaa │ 東京 │
│ 1 │ latte │ bbb │ 大阪 │
│ 2 │ mocha │ ccc │ 京都 │
╰───┴──────────┴─────┴──────╯
Constrain the definition of "alphabetic" to ASCII characters only.
>
{
"no1": [100, 200, 300],
"café": ["espresso", "latte", "mocha"],
"t or f": [true, false, null],
"hmm": ["aaa", "bbb", "ccc"],
"都市": ["東京", "大阪", "京都"],
} |
polars into-df --as-columns |
polars select (polars selector alpha --ascii-only) |
polars collect
╭───┬─────╮
│ # │ hmm │
├───┼─────┤
│ 0 │ aaa │
│ 1 │ bbb │
│ 2 │ ccc │
╰───┴─────╯
Constrain the definition of "alphabetic" to ASCII characters only and ignore whitespace.
>
{
"no1": [100, 200, 300],
"café": ["espresso", "latte", "mocha"],
"t or f": [true, false, null],
"hmm": ["aaa", "bbb", "ccc"],
"都市": ["東京", "大阪", "京都"],
} |
polars into-df --as-columns |
polars select (polars selector alpha --ascii-only --ignore-spaces) |
polars sort-by "t or f" hmm |
polars collect
╭───┬────────┬─────╮
│ # │ t or f │ hmm │
├───┼────────┼─────┤
│ 0 │ │ ccc │
│ 1 │ false │ bbb │
│ 2 │ true │ aaa │
╰───┴────────┴─────╯
Select all columns except for those with alphabetic names.
>
{
"no1": [100, 200, 300],
"café": ["espresso", "latte", "mocha"],
"t or f": [true, false, null],
"hmm": ["aaa", "bbb", "ccc"],
"都市": ["東京", "大阪", "京都"],
} |
polars into-df --as-columns |
polars select (polars selector alpha | polars selector not) |
polars sort-by no1 "t or f"|
polars collect
╭───┬─────┬────────╮
│ # │ no1 │ t or f │
├───┼─────┼────────┤
│ 0 │ 100 │ true │
│ 1 │ 200 │ false │
│ 2 │ 300 │ │
╰───┴─────┴────────╯
Select all columns except for those with alphabetic names and do not have spaces.
>
{
"no1": [100, 200, 300],
"café": ["espresso", "latte", "mocha"],
"t or f": [true, false, null],
"hmm": ["aaa", "bbb", "ccc"],
"都市": ["東京", "大阪", "京都"],
} |
polars into-df --as-columns |
polars select (polars selector alpha --ignore-spaces | polars selector not) |
polars sort-by no1 |
polars collect
╭───┬─────╮
│ # │ no1 │
├───┼─────┤
│ 0 │ 100 │
│ 1 │ 200 │
│ 2 │ 300 │
╰───┴─────╯
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https://www.nushell.sh/commands/docs/polars_selector_alpha.html
