feat: initial commit for 100.dathere.com and first exercise

lessons/0/exercise.ipynb

@@ -0,0 +1,25 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Exercise 0: Total rows"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "language_info": {
+   "name": "python"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}

lessons/0/fruits.csv

@@ -0,0 +1,4 @@
+fruit,price
+apple,2.50
+banana,3.00
+carrot,1.50

lessons/0/notes.md

@@ -0,0 +1,113 @@
+---
+jupytext:
+    text_representation:
+        extension: .md
+        format_name: myst
+kernelspec:
+    display_name: Bash
+    language: bash
+    name: bash
+---
+
+# Getting help
+
+## Listing all commands
+
+This may be your first time using qsv, so let's see what qsv has to offer. In your terminal run qsv with the `--list` flag:
+
+```{code-cell}
+:tags: ["scroll-output"]
+qsv --list
+```
+
+Here we see a list of commands and a brief description about them.[^1]
+
+## Viewing a command's help message
+
+You may view a command's help message by running:
+
+```bash
+qsv <command> --help
+```
+
+For example I may run the following to get the help message for the `headers` command:
+
+```{code-cell}
+:tags: ["scroll-output"]
+qsv headers --help
+```
+
+Usually you'll find a similar structure for other qsv commands:
+
+-   Description about the command
+-   More details
+-   Examples and/or a link to them
+-   Usage format
+-   Subcommands[^2]
+-   Arguments
+-   Options (flags)
+
+## Displaying headers of a CSV
+
+Let's try viewing the headers in the `fruits.csv` file located in `lessons/0`. Based on the command format in the "Usage" section of the help message for `qsv headers`, we'll run:
+
+```{code-cell}
+qsv headers fruits.csv
+```
+
+## Recap
+
+In this lesson we've covered how to:
+
+-   List all available qsv commands with `qsv --list`
+-   View the help message for an individual command with `qsv <command> --help`
+-   Interpret the parts of a command help message
+-   Run a command on an arbitrary CSV file, getting the headers with `qsv headers <filepath>`
+
+Now it's your turn to take on the first exercise.
+
+## Exercise 0: Total rows
+
+Using a qsv command, get the total number of rows that are in the `fruits.csv` file.
+
+[![Binder](https://mybinder.org/badge_logo.svg)](https://mybinder.org/v2/gh/dathere/100.dathere.com/main?labpath=lessons%2F0%2Fexercise.ipynb)
+
+:::{hint}
+:class: dropdown
+
+The `count` command may be useful for this exercise. Make sure to learn how `qsv count` determines the row count in order to complete this exercise as intended.
+
+:::
+
+::::{admonition} Solution
+:class: dropdown seealso
+
+As with other solutions you may see in the upcoming exercises, there may be many ways to solve an exercise with qsv. A solution could be running the command:
+
+```bash
+qsv count fruits.csv --no-headers
+```
+
+And the output should be:
+
+```bash
+4
+```
+
+:::{admonition} Why not 3?
+:class: dropdown hint
+
+The exercise requires finding the **total number of rows** in `fruits.csv`. As described in the help message for `qsv count` (you may run `qsv count -h` to get the help message):
+
+<q>Note that the **count will not include the header row (unless `--no-headers` is given)**.</q>
+
+If you run `qsv count fruits.csv` then in your terminal you should see `3` as the output. Running it again this time with the `--no-headers` flag (or `-n` for short), you get the correct number of total rows `4` which includes the header row (which is the first row in the CSV file).
+
+It may sound unusual that by using the `--no-headers` flag, the header row gets included in the row count. You may share any ideas for improvements to qsv on [qsv's GitHub discussions](https://github.com/jqnatividad/qsv/discussions).
+
+:::
+
+::::
+
+[^1]: Not all 50+ commands may be listed using `qsv --list` since features may be disabled for a given qsv binary file (e.g., OS compatibility for certain commands).
+[^2]: In this case `qsv headers` does not have any subcommands.