# Description
Fixes: #13105Fixes: #13077
This pr makes `str substring`, `bytes at` work better with negative
index.
And it also fixes the false range semantic on `detect columns -c` in
some cases.
# User-Facing Changes
For `str substring`, `bytes at`, it will no-longer return an error if
start index is larger than end index. It makes sense to return an empty
string of empty bytes directly.
### Before
```nushell
# str substring
❯ ("aaa" | str substring 2..-3) == ""
Error: nu:🐚:type_mismatch
× Type mismatch.
╭─[entry #23:1:10]
1 │ ("aaa" | str substring 2..-3) == ""
· ──────┬──────
· ╰── End must be greater than or equal to Start
2 │ true
╰────
# bytes at
❯ ("aaa" | encode utf-8 | bytes at 2..-3) == ("" | encode utf-8)
Error: nu:🐚:type_mismatch
× Type mismatch.
╭─[entry #27:1:25]
1 │ ("aaa" | encode utf-8 | bytes at 2..-3) == ("" | encode utf-8)
· ────┬───
· ╰── End must be greater than or equal to Start
╰────
```
### After
```nushell
# str substring
❯ ("aaa" | str substring 2..-3) == ""
true
# bytes at
❯ ("aaa" | encode utf-8 | bytes at 2..-3) == ("" | encode utf-8)
true
```
# Tests + Formatting
Added some tests, adjust existing tests
# Description
Fixes: https://github.com/nushell/nushell/issues/7761
It's still unsure if we want to change the `range semantic` itself, but
it's good to keep range semantic consistent between nushell commands.
# User-Facing Changes
### Before
```nushell
❯ "abc" | str substring 1..=2
b
```
### After
```nushell
❯ "abc" | str substring 1..=2
bc
```
# Tests + Formatting
Adjust tests to fit new behavior
# Description
This pr is addressing feedback from
https://github.com/nushell/nushell/pull/12277#issuecomment-2027246752
Currently I think it's fine to replace `--legacy` flag with `--guess`
one. Only use `guess_width` algorithm if `--guess` is provided.
# User-Facing Changes
So it won't be a breaking change to previous version.
# Description
@fdncred found another histogram based algorithm to detect columns, and
rewrite it in rust: https://github.com/fdncred/guess-width
I have tested it manually, and it works good with `df`, `docker ps`,
`^ps`. This pr is going to use the algorithm in `detect columns`
Fix: #4183
The pitfall of new algorithm:
1. it may not works well if there isn't too much rows of input
2. it may not works well if the length of value is less than the header
to value, e.g:
```
c1 c2 c3 c4 c5
a b c d e
g h i j k
g a a q d
a v c q q | detect columns
```
In this case, users might need to use ~~`--old`~~ `--legacy` to make it
works well.
# User-Facing Changes
User might need to add ~~`--old`~~ `--legacy` to scripts if they find
`detect columns` in their scripts broken.
# Tests + Formatting
Done
# After Submitting
NaN
fix `detect columns` with flag `-c, --combine-columns` run failed when
using some range
- fixes#9653fix#9653 the cmd detect columns with the flag -c, --combine-columns run
failed when using some range.
add unit test for the command `detect columns`
```text
Attempt to automatically split text into multiple columns.
Usage:
> detect columns {flags}
Flags:
-h, --help - Display the help message for this command
-s, --skip <Int> - number of rows to skip before detecting
-n, --no-headers - don't detect headers
-c, --combine-columns <Range> - columns to be combined; listed as a range
Signatures:
<string> | detect columns -> <table>
Examples:
Splits string across multiple columns
> 'a b c' | detect columns -n
╭───┬─────────┬─────────┬─────────╮
│ # │ column0 │ column1 │ column2 │
├───┼─────────┼─────────┼─────────┤
│ 0 │ a │ b │ c │
╰───┴─────────┴─────────┴─────────╯
Splits a multi-line string into columns with headers detected
> $'c1 c2 c3 c4 c5(char nl)a b c d e' | detect columns
╭───┬────┬────┬────┬────┬────╮
│ # │ c1 │ c2 │ c3 │ c4 │ c5 │
├───┼────┼────┼────┼────┼────┤
│ 0 │ a │ b │ c │ d │ e │
╰───┴────┴────┴────┴────┴────╯
> $'c1 c2 c3 c4 c5(char nl)a b c d e' | detect columns -c 0..1
╭───┬─────┬────┬────┬────╮
│ # │ c1 │ c3 │ c4 │ c5 │
├───┼─────┼────┼────┼────┤
│ 0 │ a b │ c │ d │ e │
╰───┴─────┴────┴────┴────╯
Splits a multi-line string into columns with headers detected
> $'c1 c2 c3 c4 c5(char nl)a b c d e' | detect columns -c -2..-1
╭───┬────┬────┬────┬─────╮
│ # │ c1 │ c2 │ c3 │ c4 │
├───┼────┼────┼────┼─────┤
│ 0 │ a │ b │ c │ d e │
╰───┴────┴────┴────┴─────╯
Splits a multi-line string into columns with headers detected
> $'c1 c2 c3 c4 c5(char nl)a b c d e' | detect columns -c 2..
╭───┬────┬────┬───────╮
│ # │ c1 │ c2 │ c3 │
├───┼────┼────┼───────┤
│ 0 │ a │ b │ c d e │
╰───┴────┴────┴───────╯
Parse external ls command and combine columns for datetime
> ^ls -lh | detect columns --no-headers --skip 1 --combine-columns 5..7
```
