Consider using f-strings PYL-C0209
Performance
Minor
8 months ago
—
8 months old
Formatting a regular string which could be a f-string
25 raise RuntimeError("Cannot access private data")
26
27 data = self.cursor.execute(
28 "SELECT id FROM userdata WHERE Name ={};".format(name)29 )
30 self.conn.commit()
31 return dataFormatting a regular string which could be a f-string
6@require_http_methods(["GET", "POST"]) # Sensitive
7def current_datetime(request):
8 now = datetime.datetime.now()
9 html = "<html><body>It is %s.</body></html>" % now10 return HttpResponse(html)
Description
f-strings are the fastest way to format strings as compared to the following methods:
- using format specifiers
% - using
format() - using
str.join - using
+operator to concatinate string - using
Template.substitute
Bad practice
Some less preferred ways to format strings are the following:
from string import Template
menu = ('eggs', 'spam', 42.4)
old_order = "%s and %s: %.2f ¤" % menu # [consider-using-f-string]
beginner_order = menu[0] + " and " + menu[1] + ": " + str(menu[2]) + " ¤"
joined_order = " and ".join(menu[:2])
format_order = "{} and {}: {:0.2f} ¤".format(menu[0], menu[1], menu[2])
named_format_order = "{eggs} and {spam}: {price:0.2f} ¤".format(eggs=menu[0], spam=menu[1], price=menu[2])
template_order = Template('$eggs and $spam: $price ¤').substitute(eggs=menu[0], spam=menu[1], price=menu[2])
Recommended
Consider using f-strings as shown below:
menu = ('eggs', 'spam', 42.4)
f_string_order = f"{menu[0]} and {menu[1]}: {menu[2]:0.2f} ¤"