mathematica

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SheetJS 2023-04-22 19:25:24 -04:00
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---
title: Mathematica
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---
:::note
This demo was last tested in 2023 April 22 in Mathematica 13.2.1
:::
[The "NodeJS" instructions](/docs/getting-started/installation/frameworks)
describe installation steps for NodeJS projects. Mathematica has built-in
features for external scripting with NodeJS. Helper functions can translate
between CSV text and Mathematica datasets or arrays.
Mathematica can also use [command-line tools](/docs/demos/desktop/cli)
## Integration Details
:::caution
Mathematica includes `ExternalEvaluate` for running scripts in an external
engine. In local testing, there were incompatibilities with recent NodeJS
versions. This demo uses the shell integration to call a command-line tool.
:::
### Command-Line Tools
`ExternalEvaluate` can run command-line tools and capture standard output:
```mathematica
cmd = "/usr/local/bin/xlsx-cli ~/Downloads/pres.numbers"
csvdata = ExternalEvaluate["Shell" -> "StandardOutput", cmd];
```
Once evaluated, `ImportString` can interpret the data as a dataset. Typically
the first row of the CSV output is the header row. The `HeaderLines` option
controls how Mathematica parses the data:
```mathematica
data = ImportString[csvdata, "Dataset", "HeaderLines" -> 1]
```
## Complete Demo
:::note
This demo was tested in macOS. The path names will differ in other platforms.
:::
1) Create the standalone `xlsx-cli` binary:
```bash
cd /tmp
npm i --save https://cdn.sheetjs.com/xlsx-latest/xlsx-latest.tgz exit-on-epipe commander@2
curl -LO https://docs.sheetjs.com/cli/xlsx-cli.js
npx nexe -t 14.15.3 xlsx-cli.js
```
This is discussed in ["Command-line Tools"](/docs/demos/desktop/cli)
2) Move the generated `xlsx-cli` to a fixed location in `/usr/local/bin`:
```bash
mkdir -p /usr/local/bin
mv xlsx-cli /usr/local/bin/
```
### Reading a Local File
3) In a new Mathematica notebook, run the following snippet:
```mathematica
SheetJSImportFile[x_] := ImportString[Block[{Print}, ExternalEvaluate[
"Shell" -> "StandardOutput",
"/usr/local/bin/xlsx-cli " <> x
]], "Dataset", "HeaderLines" -> 1]
```
4) Download <https://sheetjs.com/pres.numbers> and save to Downloads folder.
5) In the Mathematica notebook, run the new function. If the file was saved to
the Downloads folder, the path will be `"~/Downloads/pres.numbers"` in macOS:
```mathematica
data = SheetJSImportFile["~/Downloads/pres.numbers"]
```
The result should be displayed in a concise table.
### Reading from a URL
`FetchURL` downloads a file from a specified URL. This function will be wrapped
in a new function called `SheetJSImportURL`.
6) In the same notebook, run the following:
```mathematica
Needs["Utilities`URLTools`"];
SheetJSImportURL[x_] := Module[{path},(
path = FetchURL["https://sheetjs.com/pres.numbers"];
SheetJSImportFile[path]
)];
```
7) Test by downloading the test file in the notebook:
```mathematica
data = SheetJSImportURL["https://sheetjs.com/pres.numbers"]
```