import time

start = time.time()
str1 = ""
for i in range(1,10000000):
    str1 += "A"*1000
print("Concat took: " + str(time.time() - start))

start = time.time()
str1 = ""
str2 = []
for i in range(1,10000000):
    str2.append("B"*1000)
print("List collection took: " + str(time.time() - start))

start = time.time()
str1 = "\n".join(str2)
print("Final join took: " + str(time.time() - start))