Printing template literals in python "{item}" vs. "{}.format(item)"

Question

Is there a reason why/helpful way to remember which format literal is used where?
In most of the places I've learned so far, it works like this:
python
bugs = ["ants", "bees", "squash bugs", "chiggers"]
for e in bugs:
    print("There are so many {} outside!".format(e))

But, for f-string, it only works like this:
python
bugs = ["ants", "bees", "squash bugs", "chiggers"]
print("Bugs outside:")
for index, e in enumerate(bugs, 1):
    print(f'{index}. {e}')

I'm guessing there is a reason for this, but the switch from the .format method to putting the variables inside the curly braces isn't obvious to me.
Thanks!

Chris Freeman · Accepted Answer

Hey @amandae (https://teamtreehouse.com/amandae), There are many ways to format a string (https://docs.python.org/3/tutorial/inputoutput.html#input-and-output) in Python. 
The f-strings (https://docs.python.org/3/tutorial/inputoutput.html#formatted-string-literals), formatted string literals, is the latest addition, first appearing in Python 3.6 (https://docs.python.org/3/whatsnew/3.6.html#pep-498-formatted-string-literals). 
The more complex (and flexible) previous method is using the str.format() (https://docs.python.org/3/tutorial/inputoutput.html#the-string-format-method) method. This is is still widely used, and has additional features (like repeatable, reorderable fields) so expect it to stick around for a long time.
With the format method, the {} placeholders can taking on many forms:
* as order-dependent placeholders when empty: "{} before {}".format(first, last)
* as indexed-dependent placeholders when numbered: "{1} before {0}".format(goes2zero, goes2one)
* as named placeholders: "{first} before {last}".format(first=goes2first, last=goes2last)
So, about remembering the difference. The "f" in front of f-strings can be thought of as fancy, where it is a shortcut to the named placeholder version of format without having to add the .format(first=first, last=last) method. The "f" can also be thought of as fast, since f-stings have been optimized to be the fasted string handling in python!!
Post back if you need more help. Good luck!!

amandae · Answer

Thank you so much!  Your answer is wonderfully helpful!

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Printing template literals in python "{item}" vs. "{}.format(item)"

2 Answers

Chris Freeman

Chris Freeman

amandae

amandae