Numpy append is slow.ipynb

numpy-append-is-slow.ipynb

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      "name": "Numpy append is slow.ipynb",
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    "kernelspec": {
      "name": "python3",
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  "cells": [
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "view-in-github",
        "colab_type": "text"
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      "source": [
        "<a href=\"https://colab.research.google.com/gist/simecek/5280e202df1a2b39e412a7f438b2acc1/numpy-append-is-slow.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>"
      ]
    },
    {
      "metadata": {
        "id": "oymWg-2UDrnk",
        "colab_type": "code",
        "colab": {}
      },
      "cell_type": "code",
      "source": [
        "import numpy as np\n",
        "from collections import deque"
      ],
      "execution_count": 0,
      "outputs": []
    },
    {
      "metadata": {
        "id": "N3q07H-FGepZ",
        "colab_type": "text"
      },
      "cell_type": "markdown",
      "source": [
        "## List"
      ]
    },
    {
      "metadata": {
        "id": "LKG_SBvJEO_d",
        "colab_type": "code",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 52
        },
        "outputId": "6d46c457-d79c-43b2-d092-a4ac1de0a881"
      },
      "cell_type": "code",
      "source": [
        "%%time\n",
        "\n",
        "l = list()\n",
        "for i in range(10000):\n",
        "\tl.append(i)"
      ],
      "execution_count": 2,
      "outputs": [
        {
          "output_type": "stream",
          "text": [
            "CPU times: user 1.96 ms, sys: 0 ns, total: 1.96 ms\n",
            "Wall time: 1.97 ms\n"
          ],
          "name": "stdout"
        }
      ]
    },
    {
      "metadata": {
        "id": "7qzfupc8Ghlh",
        "colab_type": "text"
      },
      "cell_type": "markdown",
      "source": [
        "## Deque"
      ]
    },
    {
      "metadata": {
        "id": "LQyOQgwHD2Pg",
        "colab_type": "code",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 52
        },
        "outputId": "981caacf-da4d-434d-b23d-2ff0851e971f"
      },
      "cell_type": "code",
      "source": [
        "%%time\n",
        "\n",
        "d = deque()\n",
        "for i in range(10000):\n",
        "\td.append(i)"
      ],
      "execution_count": 3,
      "outputs": [
        {
          "output_type": "stream",
          "text": [
            "CPU times: user 1.76 ms, sys: 0 ns, total: 1.76 ms\n",
            "Wall time: 1.77 ms\n"
          ],
          "name": "stdout"
        }
      ]
    },
    {
      "metadata": {
        "id": "xyMww8GyGlFl",
        "colab_type": "text"
      },
      "cell_type": "markdown",
      "source": [
        "## Numpy (append)"
      ]
    },
    {
      "metadata": {
        "id": "l_EM2rEgEdmU",
        "colab_type": "code",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 52
        },
        "outputId": "f3816ed3-273a-4b46-e372-946cfa7a84f4"
      },
      "cell_type": "code",
      "source": [
        "%%time\n",
        "\n",
        "a = np.array([])\n",
        "for i in range(10000):\n",
        "\ta = np.append(a, [i])"
      ],
      "execution_count": 4,
      "outputs": [
        {
          "output_type": "stream",
          "text": [
            "CPU times: user 70.7 ms, sys: 947 µs, total: 71.7 ms\n",
            "Wall time: 74 ms\n"
          ],
          "name": "stdout"
        }
      ]
    },
    {
      "metadata": {
        "id": "qppFnY-QG3-5",
        "colab_type": "text"
      },
      "cell_type": "markdown",
      "source": [
        "## Numpy (allocate the array beforehand)"
      ]
    },
    {
      "metadata": {
        "id": "yvZ23jlyG0uO",
        "colab_type": "code",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 52
        },
        "outputId": "03bf9d17-0f4e-406c-e255-a724b994eb12"
      },
      "cell_type": "code",
      "source": [
        "%%time\n",
        "\n",
        "a = np.zeros(10000)\n",
        "for i in range(10000):\n",
        "\ta[i] = i"
      ],
      "execution_count": 5,
      "outputs": [
        {
          "output_type": "stream",
          "text": [
            "CPU times: user 1.62 ms, sys: 0 ns, total: 1.62 ms\n",
            "Wall time: 1.58 ms\n"
          ],
          "name": "stdout"
        }
      ]
    }
  ]
}