{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Concentration de CO2 dans l'atmosphère depuis 1958\n",
    "\n",
    "On s'intéresse à la concentration en CO2 au cours du temps depuis 1958; les données sont disponibles sur le site web [scrippsco2.ucsd.edu](https://scrippsco2.ucsd.edu/data/atmospheric_co2/primary_mlo_co2_record.html)\n",
    "\n",
    "Commençons par importer les bibliothèques nécessaires à l'analyse"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "%matplotlib inline\n",
    "import matplotlib.pyplot as plt\n",
    "import numpy as np\n",
    "import pandas as pd\n",
    "import isoweek"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Chargeons à présent les données"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "def skiprows(x):\n",
    "    return x < 62 or x in [63,64]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Données disponibles en local, téléchargement en cours\n"
     ]
    }
   ],
   "source": [
    "data_url = \"https://scrippsco2.ucsd.edu/assets/data/atmospheric/stations/in_situ_co2/monthly/monthly_in_situ_co2_mlo.csv\"\n",
    "data_path = \"./monthly_in_situ_co2_mlo.csv\"\n",
    "\n",
    "try:\n",
    "    data = pd.read_csv(data_path)\n",
    "    print(\"Données disponibles en local, téléchargement en cours\")\n",
    "except FileNotFoundError as e:\n",
    "    print(\"Données non disponibles, téléchargement...\")\n",
    "    data = pd.read_csv(data_url,skiprows=skiprows)\n",
    "    data.to_csv(data_path)\n",
    "    print(\"Téléchargement et enregistrement terminé\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
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