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Python

Posted by ANDY VAN DEN BOS
ANDY VAN DEN BOS
2,330 Points

Can you show me an example of why we would want to use the .format method over the ' + ' .join method?

In this video lesson we learned how to join strings and lists using two different methods.

flavors = ['chocolate', 'mint', 'strawberry']

', '.join(flavors)
'chocolate, mint, strawberry'
"my favorite flavors are: " + ', '.join(flavors)
'my favorite flavors are: chocolate, mint, strawberry'

"My favorite flavors are: {}".format(", ".join(flavors))
'My favorite flavors are: chocolate, mint, strawberry'

I am just looking for a deeper understanding of the two methods shown above. Why would I want to use one over the other. Can anyone give me a good example?

Thank you.

1 Answer

Kenneth Love
STAFF
Kenneth Love
Treehouse Guest Teacher
Kenneth Love
Kenneth Love
Treehouse Guest Teacher

Most of the time you want to avoid +. It's a convenience method for quickly joining some small strings. It used to be the only real way (other than % strings, which, let's not talk about those for now).

Using .format(), and the new f strings, gives you the ability to put multiple values into a string, otherwise formatted values into a string, or values that you want formatted when it goes into the string.

Some examples:

>>> names = ["Kenneth", "Alena", "Craig"]
>>> prices = [8, 2.5, 9.2232]
>>> "Some of our teachers are: {}".format(", ".join(names))
"Some of our teachers are: Kenneth, Alena, Craig"
>>> "It costs ${:.2f}".format(prices[-1])
"It costs $9.22"

There's a lot more you can do with string but this is a bit much to discuss in Python Basics, but maybe I'll do a "The Thing About Strings" workshop or something.

ANDY VAN DEN BOS
ANDY VAN DEN BOS
2,330 Points

Thanks allot Kenneth. I really appreciate the quick response and your feed back. I've dabbled a bit with C# and Ruby, but I've found your classes on Python to be the easiest to learn for me.