Can I evaluate plots?

Author: James Collier

dodona/exercises/bar-plot/config.json

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+{
+  "description": {
+    "names": {
+      "en": "Bar Plot"
+    }
+  },
+  "labels": [
+    "real-world programming"
+  ],
+  "internals": {
+    "token": "G4iAJA8szv6ihdYCfAXzZdQH_Zwp9BugYTY2t-YkRGAYBPXDcpU_UHSRE4S6WJ62",
+    "_info": "These fields are used for internal bookkeeping in Dodona, please do not change them."
+  }
+}

dodona/exercises/bar-plot/description/description.en.md

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+I've left a secret message for you in a text file [here](media/secret.txt). Because it's very
+secret I've encrypted it using a Caesar cipher.
+
+Your task is to write a function to decrypt Caesar ciphertext. First let's understand what a Caesar
+cipher does with an example:
+
+Here is some text to encrypt: `"I CAN HAZ CHEESEBURGER"`. The Caesar cipher also needs a "key" which is a number
+between 1 and 26. This number is used to "rotate" the plaintext input characters. For this example,
+the key is `1`.
+
+The first letter is `"I"`. `"I"` "rotated" by `1` is the letter after `"I"` which is `"J"`. So the
+encrypted ciphertext is `"J"` so far.
+
+The next letter is `" "`. Spaces are not changed by encryption and decryption so the encrypted
+ciphertext is now: `"J "`.
+
+The same logic applies to all lettes in the string up until `"Z"`. At this point the plaintext,
+`"I CAN HA"` has been encryped to `"J DBO IB"`. To encrypt a `"Z"` you count back again from the
+beginning of the alphabet. So the plaintext `"Z"` is encrypted to `"A"`.
+
+This is why it's called a "rotation". If you write the latin alphabet, A...Z on a circular piece of
+paper. Then again on a slightly smaller piece of paper. Rotate one of the circular pieces of paper by
+the key and this gives the mapping between plaintext letters and ciphertext letters.
+
+![Caesar cipher](https://gkaccess.com/wp-content/uploads/2020/01/Caesar_Cipher_GateKeeper_security_compliance_proximity_authentication_2fa_mfa-768x803.jpg)
+
+The final encryption of the string `"I CAN HAZ CHEESEBURGER"` with a key of `1` is then:
+`"J DBO IBA DIFFTFCVSHFS"`.
+
+Your task is to write a function to decode caesar ciphers called `decrypt`. Your function should accept
+2 arguments:
+
+- The encrypted ciphertext (as uninterpreted binary data type: `bytes`)
+- The key (type: `int`)
+
+Your function should return a `str`.
+
+You can use this template:
+
+```python
+def decrypt(ciphertext: bytes, key: int) -> str:
+  ...
+```
+
+
+You should also `print()` my message to the console using your `decrypt` function.
+You can use a key of `13` to decode my message. The message is in a file called, `"secret.txt"`.
+
+## Example
+
+```console?lang=python&prompt=>>>
+>>> decrypt(b'B NFTTBHF', 1)
+"A MESSAGE"
+>>> decrypt(b'', 12)
+""
+>>> decrypt(b'QBUN CM SIOL HUGY', 6)
+"WHAT IS YOUR NAME"
+>>> decrypt(b'HELLO WORLD', 26)
+"HELLO WORLD"
+```
+
+
+Do not forget to include a docstring on your `decrypt` function and a test function called
+`test_decrypt` that returns `"Success"` if the `decrypt` function passes all tests.

dodona/exercises/bar-plot/evaluation/expected.png

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+- tab: "Bar plot global data"
+  testcases:
+    - expression:
+        python: "submission.bar_plot_global('HadCRUT.5.0.1.0.analysis.summary_series.global.monthly.csv')"
+      return: !oracle
+        value: ""
+        oracle: "custom_check"
+        file: "test.py"
+        name: "Image check"
+        arguments: []

dodona/exercises/bar-plot/evaluation/suite.yml

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+from evaluation_utils import EvaluationResult, ConvertedOracleContext
+from matplotlib.testing.compare import compare_images
+
+def evaluate_test(context: ConvertedOracleContext):
+    context.actual.savefig("actual.png")
+    result = compare_images("actual.png", "expected.png")
+    return EvaluationResult(
+        result=result is None,
+        readable_expected="",
+        readable_actual="",
+        messages=[result] if result is not None else [],
+    )

dodona/exercises/bar-plot/evaluation/test.py

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+import csv
+from datetime import datetime
+
+import matplotlib.pyplot as plt
+
+def clean_global_data(raw: dict[str, str]) -> dict:
+    return {
+        "time": datetime.strptime(raw["Time"], "%Y-%m"),
+        "temperature": float(raw["Anomaly (deg C)"])
+    }
+
+def parse_global_data(filename: str) -> list[dict]:
+    data = []
+    with open(filename) as raw:
+        reader = csv.DictReader(raw)
+        for row in reader:
+            data.append(clean_global_data(row))
+
+def times(data: list[dict]) -> list[datetime]:
+    t = []
+    for obs in data:
+        t.append(obs["time"])
+
+    return t
+
+def temperatures(data: list[dict]) -> list[float]:
+    t = []
+    for obs in data:
+        t.append(obs["temperature"])
+    return t
+
+def bar_plot_global(filename: str):
+    data = parse_global_data(filename)
+    xaxis = times(data)
+    yaxis = temperatures(data)
+
+    return plt.bar(x=xaxis, height=yaxis)