Why 'seq' not work in a loop?

Question

for i in range(10):
    print(i, sep = ',', end = '')

It should be 0,1,2,3,4,5,6,7,8,9 ,but the truth is The sep does not work. Thanks!

Answer 1

The optional sep argument is used to define the separator between comma separated argument values that are fed to the objects parameter of print . objects is a variable argument parameter, which means it can take any number of arguments (or an unpacked iterable).

From the docs :

print(*objects, sep=' ', end='\\n', file=sys.stdout, flush=False)

Print objects to the text stream file, separated by sep and followed by end. sep, end and file, if present, must be given as keyword arguments.

All non-keyword arguments are converted to strings like str() does and written to the stream, separated by sep and followed by end. Both sep and end must be strings; they can also be None, which means to use the default values. If no objects are given, print() will just write end.

A better way of writing your code would be the following:

print(*range(10), sep=',', end='')

This uses the * operator to unpack the iterable and feed each of its elements in as arguments to the print function.

It is equivalent to:

print(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, sep=',', end='')

Answer 2

In this loop, i is always a one digit integer and this can't be seperated.

It would be like this:

print("1", sep=',', end='')
print("2", sep=',', end='')
print("3", sep=',', end='')
...