Added exercises with list comprehensions.

3 files changed, 132 insertions, 0 deletions

diff --git a/python/problems/comprehensions/std/common.py b/python/problems/comprehensions/std/common.py
new file mode 100644
index 0000000..05c7357
--- /dev/null
+++ b/python/problems/comprehensions/std/common.py
@@ -0,0 +1,78 @@
+import re
+from python.util import has_token_sequence, string_almost_equal, \
+    string_contains_number, get_tokens, get_numbers, get_exception_desc, \
+    all_tokens, has_comprehension, has_loop, almost_equal, get_ast
+from server.hints import Hint
+
+id = 20704
+number = 4
+visible = True
+
+solution = '''\
+def mean(xs):
+    return sum(xs) / len(xs)
+
+def std(xs):
+    a = mean(xs)
+    return math.sqrt(sum((x - a)**2 for x in xs) / len(xs))
+'''
+
+hint_type = {
+    'final_hint': Hint('final_hint'),
+    'no_comprehension': Hint('no_comprehension'),
+    'has_loop': Hint('has_loop')
+}
+
+def test(python, code):
+    func_name = 'std'
+    tokens = get_tokens(code)
+    ast = get_ast(code)
+    if not has_token_sequence(tokens, ['def', func_name]):
+        return False, [{'id' : 'no_func_name', 'args' : {'func_name' : func_name}}]
+
+    in_out = [
+        ([183, 168, 175, 176, 192, 180], 7.43863786814),
+        ([83, 68, 75, 76, 92, 80], 7.43863786814),
+        ([1, 1, 1], 0),
+        ([1], 0),
+        ([-3, 3], 3)
+    ]
+
+    test_in = [('{0}({1})'.format(func_name, str(l[0])), None)
+               for l in in_out]
+    test_out = [l[1] for l in in_out]
+
+    answers = python(code=code, inputs=test_in, timeout=1.0)
+    n_correct = 0
+    tin, tout = None, None
+    for i, (ans, to) in enumerate(zip(answers, test_out)):
+        corr = isinstance(ans[0], float) and almost_equal(ans[0], to, 3)
+        n_correct += corr
+        if not corr:
+            tin = test_in[i][0]
+            tout = to
+
+    passed = n_correct == len(test_in)
+    hints = [{'id': 'test_results', 'args': {'passed': n_correct, 'total': len(test_in)}}]
+    if tin:
+        hints.append({'id': 'problematic_test_case', 'args': {'testin': str(tin), 'testout': str(tout)}})
+    if passed:
+        if not has_comprehension(ast):
+            hints.append({'id': 'no_comprehension'})
+        elif has_loop(ast):
+            hints.append({'id': 'has_loop'})
+        else:
+            hints.append({'id': 'final_hint'})
+
+    return passed, hints
+
+
+def hint(python, code):
+    tokens = get_tokens(code)
+
+    # run one test first to see if there are any exceptions
+    answer = python(code=code, inputs=[(None, None)], timeout=1.0)
+    exc = get_exception_desc(answer[0][3])
+    if exc: return exc
+
+    return None
diff --git a/python/problems/comprehensions/std/en.py b/python/problems/comprehensions/std/en.py
new file mode 100644
index 0000000..8599da8
--- /dev/null
+++ b/python/problems/comprehensions/std/en.py
@@ -0,0 +1,13 @@
+id = 20704
+name = 'Standard deviation'
+
+description = '''\
+<p>(translation missing)</p>'''
+
+hint = {
+    'plan': '''\
+<p>(translation missing)</p>''',
+
+    'no_input_call': '''\
+<p>(translation missing)</p>''',
+}
diff --git a/python/problems/comprehensions/std/sl.py b/python/problems/comprehensions/std/sl.py
new file mode 100644
index 0000000..ae6e0af
--- /dev/null
+++ b/python/problems/comprehensions/std/sl.py
@@ -0,0 +1,41 @@
+import server
+mod = server.problems.load_language('python', 'sl')
+
+
+id = 20704
+name = 'Standardni odklon'
+
+description = '''\
+<p>
+Napišite funkcijo <code>std(xs)</code>, ki izračuna
+standardni odklon populacije <code>xs</code>. Formulo za standardno deviacijo je
+\[ \sigma = \sqrt{ \\frac{1}{N}\sum_{i=1}^{N} \left(x_i - \mu \\right)^2} \],
+Vrednost \( \mu \) je povprečna vrednost populacije.
+</p>
+<pre>
+>>> xs = [183, 168, 175, 176, 192, 180]
+>>> std(xs)
+7.43863786814
+</pre>
+'''
+
+plan = []
+
+hint = {
+    'final_hint': ['''\
+<p>Program je pravilen! <br>
+</p>
+'''],
+
+    'no_comprehension': ['''\
+<p>Program je sicer pravilen, vendar ne vsebuje izpeljanih seznamov ali
+generatorjev...
+</p>
+'''],
+
+    'has_loop': ['''\
+<p>Program je sicer pravilen, vendar vsebuje zanko.
+</p>
+'''],
+
+}