# Ex1 Count elements in the array arr length len arr print Elements coun

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109``` ```# Ex1: Count elements in the array arr = [1, 3, 5, 6] length = len(arr) print('Elements count:') print(length) # Ex2: Count elements equal to defined def equal_num(arr, num): count = 0 for i in arr: if i == num: count += 1 return count print('Count elements equal to 2:') equal_res = equal_num([1, 2, 1, 2, 1, 3], 2) print(equal_res) # Ex3: Sum all elements in the array arr2 = [1, 3, 5, 6, 8] sum_arr = sum(arr2) print('Sum of array:') print(sum_arr) # Ex4: Find max of elements in the array print('Max of array:') print(max(arr2)) # Ex5: Find mean of elements in the array print('Mean of array:') print(sum(arr2) / len(arr2)) # Ex6: Write elements with space as delimiter print('Splitted string:') print(' '.join(str(i) for i in arr2)) # Ex7: Multiply numbers on even positions by 2 # and numbers on odd positions by 3 arr3 = [] for i in range(0, len(arr2)): if i % 2 == 0: arr3.append(arr2[i]*2) else: arr3.append(arr2[i]*3) print('Multiplied values:') print(arr3) # Ex8: Check if all elements in the array are multiple of a number. def multiple_num(arr, num): for i in arr: if i % 7 != 0: return False return True arr4 = [7, 0, 14, 210] print('Multiple of a 7:') print(multiple_num(arr2, 7)) print(multiple_num(arr4, 7)) # Ex9: check if there is a negative number in the array arr5 = [1, 3, -5, 6, 8] def is_negative(arr): for i in arr: if i < 0: return True return False print('Contains negative:') print(is_negative(arr)) print(is_negative(arr5)) # Ex10: Leave only even numbers in the array def only_even(arr): evens = [] for i in arr: if i % 2 == 0: evens.append(i) return evens evens = only_even(arr2) print("Only even numbers:") print(evens) # Ex11: Split string into words str = "quick brown fox jumps over the lazy dog" splits = str.split(" ") print("Splitted string:") print(splits) # Ex12: Return list starting from 5th element. arr6 = [1, 3, 5, 6, 8, 7, 12, 1111, 19] print("Elements starting from 5th:") print(arr6[5:]) # Ex13: Return list excluding first and last element. print('Elements excluding first and last:') print(arr6[1:-1]) ```