adding prac: ✏️

Author: sbtries

1 Python/practice/practice01-fundamentals.md

@@ -0,0 +1,69 @@
+
+
+# Practice 1: Fundamentals
+
+For each practice problem, write a function that returns a value (not just prints it). You can then call the function a couple times to test it, comment those calls out, and move on to the next problem. An example of this format is given below.
+
+```python
+def add(a, b):
+    return a + b
+#print(add(5, 2))
+#print(add(8, 1))
+```
+
+## Problem 1
+
+Write a function that tells whether a number is even or odd (hint, compare a/2 and a//2, or use a%2)
+
+```python
+def is_even(a):
+    ...
+is_even(5) → False
+is_even(6) → True
+```
+
+
+## Problem 2
+
+Write a function that takes two ints, a and b, and returns True if one is positive and the other is negative.
+
+```python
+def opposite(a, b):
+    ...
+opposite(10, -1) → True
+opposite(2, 3) → False
+opposite(-1, -1) → False
+```
+
+## Problem 3
+
+Write a function that returns True if a number within 10 of 100.
+
+```python
+def near_100(num):
+    ...
+near_100(50) → False
+near_100(99) → True
+near_100(105) → True
+```
+
+## Problem 4
+
+Write a function that returns the maximum of 3 parameters.
+
+```python
+def maximum_of_three(a, b, c):
+    ...
+maximum_of_three(5,6,2) → 6
+maximum_of_three(-4,3,10) → 10
+```
+
+## Problem 5
+
+Print out the powers of 2 from 2^0 to 2^20
+
+`1, 2, 4, 8, 16, 32, ...`
+
+
+
+

1 Python/practice/practice02-strings.md

@@ -0,0 +1,76 @@
+
+# Practice: Strings
+
+For each practice problem, write a function that returns a value (not just prints it). You can then call the function a couple times to test it, comment those calls out, and move on to the next problem. An example of this format is given below.
+
+```python
+def add(a, b):
+    return a + b
+#print(add(5, 2))
+#print(add(8, 1))
+```
+
+
+## Problem 1
+
+Get a string from the user, print out another string, doubling every letter.
+
+```
+>>> Enter some text: hello
+hheelloo
+```
+
+## Problem 2
+
+Write a function that takes a string, and returns a list of strings, each missing a different character.
+
+```python
+missing_char('kitten') → ['itten', 'ktten', 'kiten', 'kiten', 'kittn', 'kitte']
+```
+
+## Problem 3
+Return the letter that appears the latest in the english alphabet.
+```
+>>> latest_letter('pneumonoultramicroscopicsilicovolcanoconiosis')
+the latest letter is v.
+```
+
+## Problem 4
+
+Write a function that returns the number of occurances of 'hi' in a given string.
+
+```python
+count_hi('hihi') → 2
+```
+
+## Problem 5
+
+Write a function that returns True if a given string contains the same number of 'cat' as it does 'dog'
+
+```python
+cat_dog('catdog') → True
+cat_dog('catcat') → False
+cat_dog('catdogcatdog') → True
+```
+
+
+
+
+## Problem 6
+
+Return the number of letter occurances in a string.
+```python
+def count_letter(letter, word):
+    ...
+count_letter('i', 'antidisestablishmentterianism') → 5
+count_letter('p', 'pneumonoultramicroscopicsilicovolcanoconiosis') → 2
+```
+
+## Problem 7
+
+Convert input strings to lowercase without any surrounding whitespace.
+
+```
+lower_case("SUPER!") → 'super!'
+lower_case("        NANNANANANA BATMAN        ") → 'nannananana batman'
+```

1 Python/practice/practice03-lists.md

@@ -0,0 +1,156 @@
+
+# Practice Problems: Lists
+
+
+
+For each practice problem, write a function that returns a value (not just prints it). You can then call the function a couple times to test it, comment those calls out, and move on to the next problem. An example of this format is given below.
+
+```python
+def add(a, b):
+    return a + b
+#print(add(5, 2))
+#print(add(8, 1))
+```
+
+
+
+## Problem 1
+
+Write a function using random.randint to generate an index, use that index to pick a random element of a list and return it.
+
+```
+def random_element(a):
+    ...
+
+fruits = ['apples', 'bananas', 'pears']
+random_element(fruits) could return 'apples', 'bananas' or 'pears'
+```
+
+## Problem 2
+
+Write a REPL which asks users for a list of numbers, which they enter, until they say 'done'. Then print out the list.
+
+```
+Enter a number (or 'done'): 5
+Enter a number (or 'done'): 34
+Enter a number (or 'done'): 515
+Enter a number (or 'done'): done
+[5, 34, 515]
+```
+
+
+## Problem 3
+
+Write a function that takes a list of numbers, and returns True if there is an even number of even numbers.
+
+```python
+eveneven([5, 6, 2]) → True
+eveneven([5, 5, 2]) → False
+```
+
+
+## Problem 4
+
+Print out every other element of a list, first using a while loop, then using a for loop.
+
+```
+>>> nums = [0, 1, 2, 3, 4, 5, 6, 7, 8]
+>>> print_every_other(nums)
+0, 2, 4, 6, 8
+```
+
+## Problem 5
+Write a function that returns the reverse of a list.
+
+`def reverse(nums):`
+
+## Problem 6
+Write a function to move all the elements of a list with value less than 10 to a new list and return it.
+
+`def extract_less_than_ten(nums):`
+
+## Problem 7
+Write a function to find all common elements between two lists.
+
+`def common_elements(nums1, nums2):`
+
+
+## Problem 8
+Write a function to combine two lists of equal length into one, alternating elements.
+
+```python
+def combine(nums1, nums2):
+    ...
+combine(['a','b','c'],[1,2,3]) → ['a', 1, 'b', 2, 'c', 3]
+```
+
+
+## Problem 9
+
+Given a list of numbers, and a target number, find a pair of numbers from the list that sum to a target number
+
+```python
+nums = [5, 6, 2, 3]
+target = 7
+find_pair(nums, target) → [5, 2]
+```
+
+Optional: return a list of all pairs of numbers that sum to a target value.
+
+
+## Problem 10
+
+Write a function that merges two lists into a single list, where each element of the output list is a list containing two elements, one from each of the input lists.
+
+```python
+merge([5,2,1], [6,8,2]) → [[5,6],[2,8],[1,2]]
+```
+
+
+## Problem 11
+
+Write a function `combine_all` that takes a list of lists, and returns a list containing each element from each of the lists.
+
+```python
+nums = [[5,2,3],[4,5,1],[7,6,3]]
+combine_all(nums) → [5,2,3,4,5,1,7,6,3]
+```
+
+
+## Problem 12
+
+Write a function that takes `n` as a parameter, and returns a list containing the first `n` [Fibonacci Numbers](https://en.wikipedia.org/wiki/Fibonacci_number).
+
+```python
+fibonacci(8) → [1, 1, 2, 3, 5, 8, 13, 21]
+```
+
+## Problem 13
+
+Write functions to find the minimum, maximum, mean, and (optionally) mode of a list of numbers.
+
+```python
+def minimum(nums):
+    ...
+
+def maxmimum(nums):
+    ...
+
+def mean(nums):
+    ...
+
+def mode(nums): # (OPTIONAL)
+    ...
+```
+
+
+## Problem 14
+
+Write a function which takes a list as a parameter and returns a new list with any duplicates removed.
+
+```python
+def find_unique(nums):
+    ...
+nums = [12, 24, 35, 24, 88, 120, 155, 88, 120, 155]
+unique_nums = find_unique(nums) → [12, 24, 35, 88, 120, 155]
+```

1 Python/practice/practice04-dictionaries.md

@@ -0,0 +1,45 @@
+
+# Practice 4: Dictionaries
+
+For each practice problem, write a function that returns a value (not just prints it). You can then call the function a couple times to test it, comment those calls out, and move on to the next problem. An example of this format is given below.
+
+```python
+def add(a, b):
+    return a + b
+#print(add(5, 2))
+#print(add(8, 1))
+```
+
+
+## Problem 1
+
+Given a the two lists below, combine them into a dictionary.
+
+```python
+def combine(a, b):
+    ...
+fruits = ['apple', 'banana', 'pear']
+prices = [1.2, 3.3, 2.1]
+combine(fruits, prices) -> {'apple':1.2, 'banana':3.3, 'pear':2.1}
+```
+
+
+## Problem 2
+
+Using the result from the previous problem, iterate through the dictionary and calculate the average price of an item.
+
+```python
+def average(d):
+    ...
+combined = {'apple':1.2, 'banana':3.3, 'pear':2.1}
+average(combined) -> 2.2
+```
+
+## Problem 3
+
+Average numbers whose keys start with the same letter. Output a dictionary containing those letters as keys and the averages.
+
+```python
+d = {'a1':5, 'a2':2, 'a3':3, 'b1':10, 'b2':1, 'b3':1, 'c1':4, 'c2':5, 'c3':6}
+unify(d) -> {'a':3, 'b':4, 'c':5}
+```

1 Python/practice/practice05-comprehensions.md

@@ -0,0 +1,42 @@
+
+
+# Practice 5: Comprehensions
+
+
+For each practice problem, write a function that returns a value (not just prints it). You can then call the function a couple times to test it, comment those calls out, and move on to the next problem. An example of this format is given below.
+
+```python
+def add(a, b):
+    return a + b
+#print(add(5, 2))
+#print(add(8, 1))
+```
+
+
+## Problem 1
+
+Write a comprehension to generate the first 10 powers of two.
+
+`[1, 2, 4, 8, 16, 32, 64, 128, 256, 512]`
+
+## Problem 2
+
+Write a comprehension to generate the first 10 even numbers.
+
+`[2, 4, 6, 8, 10, 12, 14, 16, 18, 20]`
+
+
+## Problem 3
+
+Write a dictionary comprehension to swap keys and values of a given dictionary. So `{'a': 1, 'b': 2}` would become `{1: 'a', 2: 'b'}`.
+
+
+## Problem 4
+
+Write a dictionary comprehension to print each letter of the alphabet and its correstponding ASCII code (check out [ord](https://docs.python.org/3.6/library/functions.html#ord))
+
+`{'a': 97, 'b': 98, 'c': 99, 'd': 100, 'e': 101, 'f': 102, 'g': 103, 'h': 104, ...}`
+
+
+
+