Rule Formatting#

Functions#

simplify_rule#

iguanas.rule_formatting.simplify_rule(rule: str) → str[source]#

Simplify a rule by removing redundant conditions on the same column.

When multiple conditions exist on the same column, keeps only the most restrictive:

  • For lower bounds (>, >=): keeps the highest threshold, preferring > over >= when equal

  • For upper bounds (<, <=): keeps the lowest threshold, preferring < over <= when equal

Parameters:

rule (str) – Rule string with conditions like (X[“col”] > val) & (X[“col”] >= val).

Returns:

Simplified rule string with redundant conditions removed. Column order is preserved based on first appearance.

Return type:

str

Examples

>>> simplify_rule('(X["amount"] >= 100.0) & (X["amount"] > 100.0)')
'(X["amount"] > 100.0)'

>>> simplify_rule('(X["amount"] < 100.0) & (X["amount"] <= 100.0)')
'(X["amount"] < 100.0)'

>>> simplify_rule('(X["a"] >= 50) & (X["b"] < 10) & (X["a"] > 100)')
'(X["a"] > 100) & (X["b"] < 10)'

to_sql#

iguanas.rule_formatting.to_sql(rule: str) → str[source]#

Convert a rule expression string to a SQL WHERE clause fragment.

Replaces X["col"] accessors with bare column names and converts & / | to AND / OR.

Parameters:

rule (str) – Rule string using X["col"] notation with & / | operators.

Returns:

SQL WHERE clause fragment with column names unquoted and boolean operators uppercased.

Return type:

str

Examples

>>> to_sql('(X["age"] >= 30) & (X["income"] < 50000)')
'(age >= 30) AND (income < 50000)'

>>> to_sql('(X["score"] >= 0.8) | (X["flag"] == 1)')
'(score >= 0.8) OR (flag == 1)'

rule_to_sql#

iguanas.rule_formatting.rule_to_sql(rule: str, table_alias: str | None = None) → str[source]#

Convert a rule expression string to a SQL WHERE clause.

Translates Iguanas rule notation (X["col"] op value) into standard SQL predicate syntax suitable for use in a WHERE or CASE WHEN clause.

Parameters:

  • rule (str) – Rule expression using X["col"] notation with & / | operators, e.g. '(X["age"] > 30) & (X["income"] < 50000)'.

  • table_alias (str | None, default=None) – Optional table or CTE alias to prefix column references with. For example, table_alias="t" turns age > 30 into t.age > 30.

Returns:

SQL WHERE clause string.

Return type:

str

Examples

>>> rule_to_sql('(X["age"] > 30) & (X["income"] < 50000)')
'(age > 30.0) AND (income < 50000.0)'

>>> rule_to_sql('(X["age"] > 30) | (X["flag"] == 1)', table_alias="t")
'(t.age > 30.0) OR (t.flag = 1.0)'