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Edit Activity 21 in Chapter 0
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‎chapter0-exercises/chapter_0_part2.ipynb‎

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@@ -141,7 +141,7 @@
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" print(choices(event, weights))"
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],
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"id": "english-federation",
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"execution_count": 46,
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"execution_count": null,
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"outputs": [
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{
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"output_type": "stream",
@@ -209,7 +209,7 @@
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" return (occurences / trials)\n"
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],
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"id": "academic-bankruptcy",
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"execution_count": 48,
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"execution_count": null,
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"outputs": []
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},
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{
@@ -238,7 +238,7 @@
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"print(3*(a**2)*(1-a)) # expected probability - does it match with the above?"
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],
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"id": "QY52_-8-kXo7",
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"execution_count": 49,
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"execution_count": null,
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"outputs": [
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{
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"output_type": "stream",
@@ -288,7 +288,7 @@
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"nums = [2, 3, 2, 4, 1, 2]"
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],
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"id": "answering-smooth",
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"execution_count": 15,
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"execution_count": null,
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"outputs": []
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},
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{
@@ -311,7 +311,7 @@
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" return set(nums)"
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],
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"id": "brilliant-exploration",
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"execution_count": 50,
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"execution_count": null,
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"outputs": []
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},
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{
@@ -337,7 +337,7 @@
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"print(remove_duplicates_1(nums))"
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],
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"id": "y9rWcRY8mEFg",
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"execution_count": 51,
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"execution_count": null,
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"outputs": [
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{
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"output_type": "stream",
@@ -372,7 +372,7 @@
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" return no_duplicates"
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],
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"id": "nutritional-pixel",
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"execution_count": 52,
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"execution_count": null,
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"outputs": []
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},
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{
@@ -398,7 +398,7 @@
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"print(remove_duplicates_2(nums))"
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],
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"id": "hyWuTXFMmQjj",
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"execution_count": 53,
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"execution_count": null,
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"outputs": [
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{
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"output_type": "stream",
@@ -442,7 +442,7 @@
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" return [num for num in numbers if num != 0]"
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],
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"id": "textile-invitation",
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"execution_count": 54,
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"execution_count": null,
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"outputs": []
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},
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{
@@ -468,7 +468,7 @@
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"print(remove_duplicates_3(nums))"
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],
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"id": "MYWECU0xnDU4",
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"execution_count": 55,
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"execution_count": null,
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"outputs": [
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{
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"output_type": "stream",
@@ -517,7 +517,7 @@
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" return numbers"
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],
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"id": "tribal-choir",
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"execution_count": 56,
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"execution_count": null,
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"outputs": []
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},
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{
@@ -543,7 +543,7 @@
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"print(remove_duplicates_4(nums))"
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],
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"id": "cV9idpAWnTsk",
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"execution_count": 57,
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"execution_count": null,
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"outputs": [
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{
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"output_type": "stream",
@@ -603,7 +603,7 @@
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" return reduce(collect_all_unique, iterable_sets)"
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],
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"id": "dangerous-wallpaper",
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"execution_count": 59,
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"execution_count": null,
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"outputs": []
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},
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{
@@ -629,7 +629,7 @@
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"print(remove_duplicates_map_reduce(nums))"
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],
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"id": "dpu8FmIP3iyC",
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"execution_count": 61,
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"execution_count": null,
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"outputs": [
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{
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"output_type": "stream",
@@ -688,7 +688,7 @@
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"d2 = {'b': 40, 'd':50}"
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],
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"id": "Lz8yzKoR4PoY",
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"execution_count": 62,
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"execution_count": null,
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"outputs": []
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},
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{
@@ -723,7 +723,7 @@
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" return combined"
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],
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"id": "sized-congo",
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"execution_count": 63,
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"execution_count": null,
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"outputs": []
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},
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{
@@ -749,7 +749,7 @@
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"print(combine_dicts(d1, d2))"
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],
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"id": "EyoM8YSe4y9U",
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"execution_count": 64,
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"execution_count": null,
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"outputs": [
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{
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"output_type": "stream",
@@ -806,7 +806,7 @@
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"matrix = [[8, 2, 3], [9, 1, 9], [5, 4, 1]]"
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],
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"id": "Omktfanw6YOd",
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"execution_count": 66,
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"execution_count": null,
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"outputs": []
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},
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{
@@ -836,7 +836,7 @@
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" return ls"
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],
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"id": "soviet-accused",
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"execution_count": 67,
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"execution_count": null,
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"outputs": []
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},
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{
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"print(flatten_1(matrix))"
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],
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"id": "FIk4mS7W6kfm",
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"execution_count": 68,
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"execution_count": null,
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"outputs": [
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{
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"output_type": "stream",
@@ -903,7 +903,7 @@
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" return row_vector"
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],
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"id": "UE1OKdqT5w1Z",
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"execution_count": 65,
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"execution_count": null,
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"outputs": []
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},
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{
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{
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"cell_type": "code",
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"metadata": {
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"id": "AOGb0HZj7Slm",
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"colab": {
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"base_uri": "https://localhost:8080/"
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},
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"id": "AOGb0HZj7Slm",
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"outputId": "b6417184-69f7-4a5a-85f7-4e8cefd1b3fb"
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},
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"source": [
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"print(flatten_2(matrix))"
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],
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"id": "AOGb0HZj7Slm",
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"execution_count": 69,
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"execution_count": null,
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"outputs": [
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{
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"output_type": "stream",
@@ -946,27 +946,86 @@
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"id": "radio-pencil"
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},
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"source": [
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"## Activity: Obtain the trace of a given square matrix"
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"## Activity 21: Compute the Trace\n",
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"\n",
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"The *trace of a square matrix* is a concept from linear algebra. According to [Wikipedia](https://en.wikipedia.org/wiki/Trace_%28linear_algebra%29), it is \"defined to be the sum of elements on the main diagonal (from the upper left to the lower right) of $A$.\" Here, the Wikipedia editors simply use $A$ as a variable to represent our square matrix.\n",
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"\n",
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"You are given a 2D list of numbers, `matrix`. You may assume it has the same number of rows as it has columns. How would you write Python code to compute its trace? "
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],
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"id": "radio-pencil"
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},
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{
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"cell_type": "markdown",
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"metadata": {
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"id": "EdjPaZBxRoZa"
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},
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"source": [
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"### Example Input"
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],
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"id": "EdjPaZBxRoZa"
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},
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{
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"cell_type": "code",
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"metadata": {
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"id": "CgdIeZLVRqGA"
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},
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"source": [
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"matrix = [[8, 2, 3], [9, 1, 9], [5, 4, 1]]"
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],
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"id": "CgdIeZLVRqGA",
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"execution_count": 2,
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"outputs": []
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},
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{
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"cell_type": "markdown",
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"metadata": {
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"id": "YsyWOrzbRen0"
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},
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"source": [
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"### Solution: Using `enumerate`"
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],
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"id": "YsyWOrzbRen0"
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},
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{
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"cell_type": "code",
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"metadata": {
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"id": "violent-tactics",
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"outputId": "a8957164-aefd-4b90-b0c2-76f1639c9368"
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"id": "violent-tactics"
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},
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"source": [
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"def trace(matx):\n",
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" c = 0\n",
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"def trace(matrix):\n",
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" sum_diagonal = 0\n",
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" for index_row, row in enumerate(matrix):\n",
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" c += matrix[index_row][index_row]\n",
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" return c\n",
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"\n",
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"print(trace(matrix)) "
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" sum_diagonal += matrix[index_row][index_row]\n",
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" return sum_diagonal"
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],
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"id": "violent-tactics",
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"execution_count": null,
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"execution_count": 1,
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"outputs": []
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},
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{
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"cell_type": "markdown",
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"metadata": {
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"id": "LBBairKbRige"
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},
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"source": [
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"#### Test Out Solution Code"
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],
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"id": "LBBairKbRige"
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},
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{
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"cell_type": "code",
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"metadata": {
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"colab": {
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"base_uri": "https://localhost:8080/"
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},
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"id": "mT_Y7FSORnFm",
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"outputId": "cd87e58b-1808-4633-9839-ee941d9d715a"
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},
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"source": [
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"print(trace(matrix)) "
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],
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"id": "mT_Y7FSORnFm",
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"execution_count": 3,
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"outputs": [
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{
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"output_type": "stream",

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