Consider using f-strings PYL-C0209
Performance
Minor
a year ago
—
a year old
Formatting a regular string which could be a f-string
10def get_aws_iot_certs(device_id):
11 certs_dir = os.getenv('CERTS_DIR')
12 root_ca_cert = os.path.join(certs_dir, "AmazonRootCA1.pem") # Adjust per your Root CA settings
13 device_cert = os.path.join(certs_dir, "{}-certificate.pem.crt".format(device_id))14 device_private_key = os.path.join(certs_dir, "{}-private.pem.key".format(device_id))
15 assert os.path.exists(root_ca_cert), "Root CA Certificate not found"
16 assert os.path.exists(device_cert), "Device Certificate not found"Formatting a regular string which could be a f-string
11 certs_dir = os.getenv('CERTS_DIR')
12 root_ca_cert = os.path.join(certs_dir, "AmazonRootCA1.pem") # Adjust per your Root CA settings
13 device_cert = os.path.join(certs_dir, "{}-certificate.pem.crt".format(device_id))
14 device_private_key = os.path.join(certs_dir, "{}-private.pem.key".format(device_id))15 assert os.path.exists(root_ca_cert), "Root CA Certificate not found"
16 assert os.path.exists(device_cert), "Device Certificate not found"
17 assert os.path.exists(device_private_key), "Device Private Key not found"
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} ¤"