# F5_6
# open(fil, 'w'): Creates a file. Existing files with the same name will be erased
# open(fil, 'r'): Open the file for reading. Throws and exception if the file doesn't exists.
# open(fil, 'a'): Append (add) to existing file 
# open(fil, 'x'): Creates a new file. Throws and exception if the file exists.

# Ex 1
filnamn = input('Name of file? ') # e.g. personer.txt
fil = open(filnamn, 'r', encoding='utf-8') #utf-8 for åäö. 
print(fil.read()) # Reads the whole file, returns a string
for rad in fil:
   print(rad, end='') # Gives two EOL without end='' 
fil.close() 

# Ex 2
filnamn = input('Name of file you want to create?  ')
fil_objekt = open(filnamn, 'w', encoding='utf-8') # Test 'a' for append
print('Print a text, end with 0:')
rad = input('Print a line:')
while rad !='0':
    fil_objekt.write(rad+'\n') # OR print(rad,file=fil_objekt)
    rad = input('Print one more line, or 0:')
fil_objekt.close()

# cont. Ex 2
print('\nContent in file', filnamn)
fil = open(filnamn, 'r', encoding='utf-8') 
for rad in fil:
    print(rad, end='') 
fil.close()
print()
print()

# Ex 3
# readfile = 'personer.txt' 
# writefile = 'friends.txt'
# with open(readfile, 'r') as f1, open(writefile, 'w') as f2: # Test 'x'
#     for person in f1: #Read a line from the file f1 refers to
#         if 'Niklas' in person:
#             continue # Skip Niklas
#         f2.write(person)
# print('Content in file friends.txt') 
# 
# fil = open(writefile, 'r', encoding='utf-8') #Must open the file again
# for rad in fil:
#     print(rad, end='')
# fil.close()