There must already exist a gazillion articles about how to do this; but one more won’t hurt, right?

Suppose you have a list, called alist, as the following:

In [2]: alist
Out[2]: ['apple', 'banana', 'pear']

To create a string from “alist” with a comma separator, we can do this:

In [3]: ','.join(alist)
Out[3]: 'apple,banana,pear'

Basically, you can place a desired separator in the ',' or omit it totally.