hw3

br/Q1.py

@@ -0,0 +1,26 @@
+import math
+
+
+def time_diff(h1, m1, s1, h2, m2, s2):
+    hour, min, sec = "", "", ""
+
+    return hour, min, sec
+
+
+def f(x, y):
+    numerator = (
+        x ** 2 + (math.e ** (1 / (math.sin(2 * math.pi * y))))) ** (1/3)
+    denominator = math.log(x ** (1 / 2), 2)
+
+    # round the input to 3 decimal places
+
+
+def shift_right(list_A, list_B):
+    """
+          list A = [1,2,3,4]
+          list B = [a,b,c]
+
+          [a,b,c,1]
+        """
+
+    pass

br/Q2_1.py

@@ -0,0 +1,11 @@
+def something(s, k):
+    """
+      split the string s
+
+      k = 1 : return all numbers in the array
+      k = 2 : return all strings in the array
+
+      returns ["list", "of, "words"]
+      or ["1", "4", "6"]
+    """
+    pass

br/Q2_2.py

@@ -0,0 +1,16 @@
+def flow_chart(a):
+    """
+    write from flow chart
+    """
+    l1, l2, l3 = [], [], []
+
+    i = 0
+    while i < len(a):
+        if a[i] % 2 == 0:
+            l1.append(a[i])
+        elif a[i] % 3 == 0:
+            l2.append(a[i])
+        else:
+            l3.append(a[i])
+
+    return [l1, l2, l3]

br/Q3.py

@@ -0,0 +1,38 @@
+# file input
+
+def split_words(filename):
+    """
+    read the file, clean the words (only alnums), convert to lowercase and return them as an array
+    returns ["the", "clean", "words"]
+    """
+
+    pass
+
+
+def get_word_frequency(w):
+    """
+      returns the word frequencies, sorted by descending order of the frquencies and character order
+
+      returns [["the", 2], ["a", 1], ["words", 1]]
+    """
+    pass
+
+
+def cut_threshold(w, thresh=2):
+    """
+      returns the word frequency array, but cut by a threshold
+
+      input
+
+      [["the", 2], ["a", 1], ["words", 1]]
+      1
+
+      returns
+      [["the", 2]]
+    """
+    pass
+
+
+def main():
+    # call all functions
+    pass

br/Q4.py

@@ -0,0 +1,2 @@
+# bwt econding
+# https://en.wikipedia.org/wiki/Burrows%E2%80%93Wheeler_transform

midterm/lesson02 - string.py → exam preparation/02 - string.py

@@ -1,3 +1,5 @@
+# TODO Provide more examples and explanations
+
 # String
 
 s = "Hello"

midterm/lesson04 - looping.py → exam preparation/04 - looping.py

@@ -1,3 +1,5 @@
+# TODO Provide more advanced examples and explanations
+
 # Repetition
 
 # 'While' loop

midterm/lesson05 - files IO.py → exam preparation/05 - files IO.py

@@ -1,3 +1,5 @@
+# TODO Provide more examples and explanations
+
 
 # Open a File
 
@@ -108,6 +110,7 @@
 
 f3 = open("result.txt", "w")
 
-b = [" ".join(i) for i in a]    # ["6210202002 22", "6210202002 22", "6210202002 22"]
+# ["6210202002 22", "6210202002 22", "6210202002 22"]
+b = [" ".join(i) for i in a]
 
-f3.write("\n".join(b))   #  "6210202002 22\n6210202002 22\n6210202002 22"
+f3.write("\n".join(b))  # "6210202002 22\n6210202002 22\n6210202002 22"

exam preparation/08 - dictionary.py

@@ -0,0 +1,172 @@
+# Dictionary
+
+# Dictionaries are used to store data values in key:value pairs.
+
+# =================================
+
+# Accessing data from a dictionry
+
+# A dictionary is kinda like a list
+# For a list, you use an index to get a value
+
+import time
+a = [1, 2, 3, 4]
+print(a[1])  # 2
+
+# For a dictionary, you use a key to get a value
+
+a = {"one": 1, "two": 2, "three": 3, "four": 4}
+print(a["one"])  # 1
+
+
+grades = {"6130186221": "A", "6230221221": "A",
+          "6231009821": "B", "6230543921": "C",
+          "6230431521": "B", "6230276821": "A"}
+
+print(grades["6130186221"])  # A
+
+# You can also use a variable as a key
+
+a = {"one": 1, "two": 2, "three": 3, "four": 4}
+key = "one"
+print(a[key])  # 1
+
+# =================================
+
+# Assigning data to a dictionary
+a = {"one": 1, "two": 2, "three": 3, "four": 4}
+a["five"] = 5
+
+b = "six"
+a[b] = 6
+
+# =================================
+
+# Keys and Values can be any type of data
+
+my_dict = {"weather": "sunny", "temperature": 25, "wind": "calm",
+           "humidity": 0.5, "id101": [1, 2, 3, 4], 101: 100, }
+
+
+# But floating point keys are not encouraged
+
+my_dict = {0.1: 'a', 0.2: 'b', 0.3: 'c', 0.4: 'd'}
+k = 0.1
+print(my_dict[k])  # a
+k += 0.1  # 0.2
+print(my_dict[k])  # b
+k += 0.1  # 0.30000000000000001
+print(my_dict[k])  # erro
+
+# =================================
+
+# Checking if k is in a dictionary
+# Used for checking if a key is in a dictionary
+
+a = {"one": 1, "two": 2, "three": 3, "four": 4}
+print("one" in a)  # True
+print("five" in a)  # False
+
+# =================================
+
+# Example: Checking if id is in dictionary
+
+
+def read_data():
+    x = input().split(", ")
+    d = {"ID": x[0],
+         "Name": x[1],
+         "Birthdate": [int(x[2]), int(x[3]), int(x[4])]}
+    return d
+
+
+student1 = {"ID": "5830000021",
+            "Name": "Pranpriya M.",
+            "Birthdate": [27, 3, 1997]}
+student2 = read_data()
+print(student2)
+# =================================
+
+
+# Looping over a dictionary
+# You can loop over a dictionary using a for loop
+
+a = {"one": 1, "two": 2, "three": 3, "four": 4}
+for key in a:
+    print(key, a[key])
+
+# OUTPUT
+# one 1
+# two 2
+# three 3
+# four 4
+
+# =================================
+
+# dict.keys(), dict.values(), dict.items()
+# Returns a list of keys, values, or key:value pairs
+
+a = {"one": 1, "two": 2, "three": 3, "four": 4}
+print(a.keys())  # ['one', 'two', 'three', 'four']
+print(a.values())  # [1, 2, 3, 4]
+print(a.items())  # [('one', 1), ('two', 2), ('three', 3), ('four', 4)]
+
+
+# You can also loop over a dictionary using the items() method
+
+a = {"one": 1, "two": 2, "three": 3, "four": 4}
+for key, value in a.items():   # destructing from a list
+    print(key, value)
+
+# =================================
+
+# Bonus
+
+# looping over a list of sorted keys
+
+a = {"one": 1, "two": 2, "three": 3, "four": 4}
+
+for key in sorted(a.keys()):
+    print(key, a[key])
+
+
+# sorting dictionary.items() by value
+
+a = {"one": 1, "two": 2, "three": 3, "four": 4}
+for v, k in sorted([(v, k) for k, v in a.items()]):
+    print(v, k)
+
+# =================================
+
+# Bonus: Dictionary Comprehension
+
+source = [("one", 1), ("two", 2), ("three", 3), ("four", 4)]
+d = {k: v for k, v in source}
+
+# =================================
+
+# Example: Dict access time
+
+
+def search_all(X):
+    b = time.time()
+    n = len(X)
+    for i in range(n):
+        if i in X:     # True
+            pass
+    for i in range(n):
+        if (n+1) in X:  # False
+            pass
+    print(time.time() - b)
+
+
+n = 10000
+L = []
+for i in range(n):
+    L.append(i)
+D = {}
+for i in range(n):
+    D[i] = i
+
+search_all(L)
+search_all(D)