fill and comprehension

fill and comprehension.ipynb

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      "source": "別々に作られた `Int64[]` と `Int64[]` は区別可能な互いに異なるオブジェクトになる。"
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      "source": "別々に作られた `Int64[]` と `Int64[]` の「値」は等しい。"
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      "source": "Int64[] == Int64[]",
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      "source": "n = 3",
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    {
      "metadata": {},
      "cell_type": "markdown",
      "source": "`fill(Int64[], 5)` は互いに完全に同一の `Int64[]` で埋められた配列を作る。"
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      "cell_type": "code",
      "source": "@show a = fill(Int64[], n);",
      "execution_count": 4,
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          "name": "stdout",
          "output_type": "stream",
          "text": "a = fill(Int64[], n) = [Int64[], Int64[], Int64[]]\n"
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      "cell_type": "code",
      "source": "all(a[i] === a[j] for i in 1:n-1 for j in i+1:n)",
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    {
      "metadata": {},
      "cell_type": "markdown",
      "source": "`[Int64[] for _ in 1:5]` は互いに異なる `Int64[]` で埋められた配列を作る。"
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    {
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      "cell_type": "code",
      "source": "@show b = [Int64[] for _ in 1:n];",
      "execution_count": 6,
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          "output_type": "stream",
          "text": "b = [Int64[] for _ = 1:n] = [Int64[], Int64[], Int64[]]\n"
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      "cell_type": "code",
      "source": "all(b[i] !== b[j] for i in 1:n-1 for j in i+1:n)",
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      "cell_type": "code",
      "source": "push!(a[1], 666)\npush!(b[1], 666)\n@show a b;",
      "execution_count": 8,
      "outputs": [
        {
          "name": "stdout",
          "output_type": "stream",
          "text": "a = [[666], [666], [666]]\nb = [[666], Int64[], Int64[]]\n"
        }
      ]
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      "cell_type": "code",
      "source": "push!.(a, 111)\npush!.(b, 111)\n@show a b;",
      "execution_count": 9,
      "outputs": [
        {
          "name": "stdout",
          "output_type": "stream",
          "text": "a = [[666, 111, 111, 111], [666, 111, 111, 111], [666, 111, 111, 111]]\nb = [[666, 111], [111], [111]]\n"
        }
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