li = [1, 3, 2, 6, 7, 3, 4, 3, 2, 5]

# 1.) Gerade Zahlen aus einer Liste extrahieren

# Aufgabe: Eine Liste mit allen geraden Zahlen zurückgeben

# a) for loop
def even_num_for(li):
    even_list = []
    
    for i in li:
        if i % 2 == 0:
            even_list.append(i)
    return even_list

# b) lambda function with filter
def even_num_lambda(li):
    return list(filter(lambda i: i % 2 == 0, li))

# c) list comprehension
def even_num_list_comprehension(li):
    return [i for i in li if i % 2 == 0]

# d) while loop
def even_num_while(li):
    i = 0
    even_list = []
    while i < len(li):
        if li[i] % 2 == 0:
            even_list.append(li[i])
        i += 1
    return even_list

print(f"1. a) {even_num_for(li)}") # a)
print(f"1. b) {even_num_lambda(li)}") # b)
print(f"1. c) {even_num_list_comprehension(li)}") # c)
print(f"1. d) {even_num_while(li)}") # d)

# 2.) Elemente umwandeln

# Aufgabe: Alle Elemente der Liste li in den Typ str umwandeln

# a) for loop
def to_string_for(li):
    string_list = []
    for i in li:
        string_list.append(str(i))
    return string_list

# b) lambda function
def to_string_lambda(li):
    return list(map(lambda i: str(i), li))

# c) lambda function
def to_string_map(li):
    return list(map(str, li))

# d) lsit comprehension
def to_string_list_comprehension(li):
    return [str(i) for i in li]

# e) lsit comprehension
def to_string_while(li):
    i = 0
    string_list = []
    while i < len(li):
        string_list.append(str(li[i]))
        i += 1
    return string_list

print(f"2. a) {to_string_for(li)}") # a)
print(f"2. b) {to_string_lambda(li)}") # b)
print(f"2. c) {to_string_map(li)}") # c)
print(f"2. d) {to_string_list_comprehension(li)}") # d)
print(f"2. e) {to_string_while(li)}") # e)