how to add on to an already existing file in python code example

Example 1: python append to file

with open(filename, "a+") as f:
  f.write('Hello World')

Example 2: python append a file and read

f = open(filelocation/name, "a")
f.write("Now the file has more content!")
f.close()

#open and read the file after the appending:
f = open("C:/test/input.txt", "r")
print(f.read())