Output of a sequence (Collatz) in Display and as a Textfile

Question

The following snippet gives me a comma-separated list in the display:

X = 19     # Start
N = 7      # Length
def f(x, n):
    yield x
    for k in range(0, n):
        if x % 2 == 0:
            x = x / 2
        else:
            x = 3*x + 1
        yield x
print(", ".join(map(str, f(X, N))))
f = file('collatz\N.txt','w')  # gives an empty file and is not named correctly
# f.write(str(f(X,N))  Does not work

How can I have that line-separated (like at default) as a good named textfile, like collatz19.txt ?

So the display-output is ok. I need the textfile-output _too_, and do no know the commands.

Perhaps join around a line feed: `print("\n".join(map(str, f(X, N))))` — quamrana, Nov 10 '19 at 17:27
btw Your code could be improved by using integer division: `x = x // 2` — quamrana, Nov 10 '19 at 17:28
Yes ok. But I need the output as a textfile and I do not know how to create. — cis, Nov 10 '19 at 17:33
Please update your question with the code you have tried that attempts to write to a text file. — quamrana, Nov 10 '19 at 17:37

quamrana · Accepted Answer · 2019-11-10T18:10:31.057

1

You have two options to write to the file:

# Write the whole file in one string
with open('collatz\N.txt','w') as fn:
    one_string = "\n".join(map(str, f(X, N)))
    fn.write(one_string + '\n')

or write to the file a line at a time:

with open(r'collatz\Ng.txt','w') as fn:
    gen = f(X, N)
    for line in gen:
        fn.write(str(line)+'\n')

edited Nov 10 '19 at 18:10

answered Nov 10 '19 at 18:03

quamrana

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Thx, I used `with open('collatz{0}.txt'.format(X),'w') as fn: ....` – cis Nov 10 '19 at 18:44

Output of a sequence (Collatz) in Display and as a Textfile

1 Answers1