{"id":5623,"date":"2019-09-30T13:03:06","date_gmt":"2019-09-30T18:03:06","guid":{"rendered":"https:\/\/www.rushworth.us\/lisa\/?p=5623"},"modified":"2019-09-30T13:03:06","modified_gmt":"2019-09-30T18:03:06","slug":"python-f-strings","status":"publish","type":"post","link":"https:\/\/www.rushworth.us\/lisa\/?p=5623","title":{"rendered":"Python f-strings"},"content":{"rendered":"

I’m accustomed to using variables directly in strings — most of my scripting experience was with Bash, Perl, and PHP. It’s something I have to think about when I would write Java or C++ code, and it’s one of the few things that struck me as a step backward in Python. This is basically the advantage that kwargs have over args, except changing a string common where changing a function definition is pretty rare.<\/p>\n

I’ve taken to using the arg identifier numbers in the print statement.<\/p>\n

>>> first=”Lisa”
\n>>> last=”Rushworth”
\n>>> print(“Hi {0}, you are {0} {1}.”.format(first, last))
\nHi Lisa, you are Lisa Rushworth.<\/p>\n

This allows me to append a new variable to the format argument list and use it anywhere in the string
\n>>> salutation=”Hello”
\n>>> print(“{2} {0}, you are {0} {1}.”.format(first, last, salutation))
\nHello Lisa, you are Lisa Rushworth.<\/p>\n

Python 3 introduced f-strings<\/a>, which go beyond the functionality I was missing. You *can* use variable names within the string:<\/p>\n

>>> print(f”{salutation} {first}, you are {first} {last}”)
\nHello Lisa, you are Lisa Rushworth<\/p>\n

You can have multi-line strings — notice that newlines aren’t being magically added. If you *want* newlines, add \\n!<\/p>\n

>>> strString = (
\n… f”{salutation} {first}, ”
\n… f”You are {first} {last} ”
\n… f”And I have more ”
\n… f”data down here”
\n… )
\n>>> print(strString)
\nHello Lisa, You are Lisa Rushworth And I have more data down here<\/p>\n

But you can also perform operations:
\n>>> print(f”{2 ** 3}”)
\n8<\/p>\n

And use the f-string in classes
\n>>> class MyThing:
\n… def __init__(self, thing1, thing2, thing3):
\n… self.thing1 = thing1
\n… self.thing2 = thing2
\n… self.age = thing3
\n…
\n… def __str__(self):
\n… return f”{self.thing1} has 2 {self.thing2} and 3 {self.age}.”
\n…
\n>>>
\n>>> thingSample = MyThing(“Something1”, “Something2”, “Something3″)
\n>>> print(f”{thingSample}”)
\nSomething1 has 2 Something2 and 3 Something3.<\/p>\n

What if you need to have a literal curly brace?
\n>>> print(f”Hi {first}, this output needs a {{curly brace}}”)
\nHi Lisa, this output needs a {curly brace}<\/p>\n","protected":false},"excerpt":{"rendered":"

I’m accustomed to using variables directly in strings — most of my scripting experience was with Bash, Perl, and PHP. It’s something I have to think about when I would write Java or C++ code, and it’s one of the few things that struck me as a step backward in Python. This is basically the …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[33],"tags":[664],"class_list":["post-5623","post","type-post","status-publish","format-standard","hentry","category-coding","tag-python"],"_links":{"self":[{"href":"https:\/\/www.rushworth.us\/lisa\/index.php?rest_route=\/wp\/v2\/posts\/5623","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.rushworth.us\/lisa\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.rushworth.us\/lisa\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.rushworth.us\/lisa\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.rushworth.us\/lisa\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5623"}],"version-history":[{"count":1,"href":"https:\/\/www.rushworth.us\/lisa\/index.php?rest_route=\/wp\/v2\/posts\/5623\/revisions"}],"predecessor-version":[{"id":5624,"href":"https:\/\/www.rushworth.us\/lisa\/index.php?rest_route=\/wp\/v2\/posts\/5623\/revisions\/5624"}],"wp:attachment":[{"href":"https:\/\/www.rushworth.us\/lisa\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5623"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rushworth.us\/lisa\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5623"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rushworth.us\/lisa\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5623"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}