Minor Math Sum Additions (#2007)

* Move sum tests into math directory

* Move sum documentation over to math documentation

One sum example already existed in the math examples and a few of the others were outdated and didn't work, so I only moved one over, and updated their output

* Remove no-longer-in-use mod statement

crates/nu-cli/tests/commands/mod.rs

@@ -44,7 +44,6 @@ mod split_by;
 mod split_column;
 mod split_row;
 mod str_;
-mod sum;
 mod touch;
 mod trim;
 mod uniq;

docs/commands/math.md

@@ -117,6 +117,13 @@ To get the average of the file sizes in a directory, simply pipe the size column
 ────────────┴────────
 ```
 
+To get the sum of the characters that make up your present working directory.
+
+```shell
+> pwd | split row / | size | get chars | math sum
+50
+```
+
 ## Errors
 
 `math` functions are aggregation functions so empty lists are invalid

docs/commands/sum.md

@@ -1,44 +0,0 @@
-# sum
-This command allows you to calculate the sum of values in a column.
-
-## Examples
-To get the sum of the file sizes in a directory, simply pipe the size column from the ls command to the sum command.
-
-```shell
-> ls | get size | math sum
-━━━━━━━━━
- value
-━━━━━━━━━
- 51.0 MB
-━━━━━━━━━
-```
-
-To get the sum of the characters that make up your  present working directory.
-```shell
-> pwd | split-row / | size | get chars | math sum
-━━━━━━━━━
- <value>
-━━━━━━━━━
-21
-━━━━━━━━━
-```
-
-Note that sum only works for integer and byte values. If the shell doesn't recognize the values in a column as one of those types, it will return an error.
-One way to solve this is to convert each row to an integer when possible and then pipe the result to `sum`
-
-```shell
-> open tests/fixtures/formats/caco3_plastics.csv | get tariff_item | math sum
-error: Unrecognized type in stream: Primitive(String("2509000000"))
-- shell:1:0
-1 | open tests/fixtures/formats/caco3_plastics.csv | get tariff_item | math sum
-  | ^^^^ source
-```
-
-```shell
-> open tests/fixtures/formats/caco3_plastics.csv | get tariff_item | str --to-int | math sum
-━━━━━━━━━━━━━
- <value>
-─────────────
- 29154639996
-━━━━━━━━━━━━━
-```