Formatting string mixes implicitly and explicitly numbered fields¶
ID: py/str-format/mixed-fields
Kind: problem
Security severity:
Severity: error
Precision: high
Tags:
- quality
- reliability
- correctness
Query suites:
- python-security-and-quality.qls
Click to see the query in the CodeQL repository
A formatting expression, that is an expression of the form the_format.format(args) or format(the_format, args), can use explicitly numbered fields, like {1}, or implicitly numbered fields, such as {}, but it cannot use both. Doing so will raise a ValueError.
Recommendation¶
Use either explicitly numbered fields or implicitly numbered fields, but be consistent.
Example¶
In the following example the formatting uses both implicit, {}, and explicit, {1}, numbering for fields, which is illegal.
def illegal_format():
"{} {1}".format("spam", "eggs")
References¶
Python Library Reference: String Formatting.