function for extracting data from lists

[Paulman]

Thanks for the help, I'm nearly there.... hopefully: now I have the code below that works and gives the last value of the list as you said. Then I tried to use "append" in order to have all the values (or names) and from my understanding I should append the output of each iteration inside the loop, but still get error "'float' object has no attribute 'append'", as per the below code. So how can I append each output from the for loop to the previous one in order to get the desired results in one line, e.g. [19.75, 20.06, 17.94, 18.77, 20.34]?

def main(list_1):
    return main
  
list_1 = [
    {'name': 'Jerome', 'weight': 3.38, 'wingspan': 49.96, 'length': 19.75},
    {'name': 'Ibraheem', 'weight': 3.08, 'wingspan': 50.59, 'length': 20.6},
    {'name': 'Tiana', 'weight': 0.81, 'wingspan': 47.86, 'length': 17.94},
    {'name': 'Lucas', 'weight': 3.33, 'wingspan': 48.27, 'length': 18.77},
    {'name': 'Rickie', 'weight': 4.4, 'wingspan': 51.0, 'length': 20.34}
]
  
def get_data(data,key):
    y = []
    for x in data:
      y=x[key]
      y.append(x)
    return y
data = list_1
get_data(list_1,'length')
output = get_data(list_1, 'length')
print(output, end=" ")