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from __future__ import annotations
import typing as t
import sqlglot
from sqlglot import expressions as exp
from sqlglot.dataframe.sql.types import DataType
from sqlglot.helper import flatten, is_iterable
if t.TYPE_CHECKING:
from sqlglot.dataframe.sql._typing import ColumnOrLiteral
from sqlglot.dataframe.sql.window import WindowSpec
class Column:
def __init__(self, expression: t.Optional[t.Union[ColumnOrLiteral, exp.Expression]]):
if isinstance(expression, Column):
expression = expression.expression # type: ignore
elif expression is None or not isinstance(expression, (str, exp.Expression)):
expression = self._lit(expression).expression # type: ignore
expression = sqlglot.maybe_parse(expression, dialect="spark")
if expression is None:
raise ValueError(f"Could not parse {expression}")
self.expression: exp.Expression = expression
def __repr__(self):
return repr(self.expression)
def __hash__(self):
return hash(self.expression)
def __eq__(self, other: ColumnOrLiteral) -> Column: # type: ignore
return self.binary_op(exp.EQ, other)
def __ne__(self, other: ColumnOrLiteral) -> Column: # type: ignore
return self.binary_op(exp.NEQ, other)
def __gt__(self, other: ColumnOrLiteral) -> Column:
return self.binary_op(exp.GT, other)
def __ge__(self, other: ColumnOrLiteral) -> Column:
return self.binary_op(exp.GTE, other)
def __lt__(self, other: ColumnOrLiteral) -> Column:
return self.binary_op(exp.LT, other)
def __le__(self, other: ColumnOrLiteral) -> Column:
return self.binary_op(exp.LTE, other)
def __and__(self, other: ColumnOrLiteral) -> Column:
return self.binary_op(exp.And, other)
def __or__(self, other: ColumnOrLiteral) -> Column:
return self.binary_op(exp.Or, other)
def __mod__(self, other: ColumnOrLiteral) -> Column:
return self.binary_op(exp.Mod, other)
def __add__(self, other: ColumnOrLiteral) -> Column:
return self.binary_op(exp.Add, other)
def __sub__(self, other: ColumnOrLiteral) -> Column:
return self.binary_op(exp.Sub, other)
def __mul__(self, other: ColumnOrLiteral) -> Column:
return self.binary_op(exp.Mul, other)
def __truediv__(self, other: ColumnOrLiteral) -> Column:
return self.binary_op(exp.Div, other)
def __div__(self, other: ColumnOrLiteral) -> Column:
return self.binary_op(exp.Div, other)
def __neg__(self) -> Column:
return self.unary_op(exp.Neg)
def __radd__(self, other: ColumnOrLiteral) -> Column:
return self.inverse_binary_op(exp.Add, other)
def __rsub__(self, other: ColumnOrLiteral) -> Column:
return self.inverse_binary_op(exp.Sub, other)
def __rmul__(self, other: ColumnOrLiteral) -> Column:
return self.inverse_binary_op(exp.Mul, other)
def __rdiv__(self, other: ColumnOrLiteral) -> Column:
return self.inverse_binary_op(exp.Div, other)
def __rtruediv__(self, other: ColumnOrLiteral) -> Column:
return self.inverse_binary_op(exp.Div, other)
def __rmod__(self, other: ColumnOrLiteral) -> Column:
return self.inverse_binary_op(exp.Mod, other)
def __pow__(self, power: ColumnOrLiteral, modulo=None):
return Column(exp.Pow(this=self.expression, expression=Column(power).expression))
def __rpow__(self, power: ColumnOrLiteral):
return Column(exp.Pow(this=Column(power).expression, expression=self.expression))
def __invert__(self):
return self.unary_op(exp.Not)
def __rand__(self, other: ColumnOrLiteral) -> Column:
return self.inverse_binary_op(exp.And, other)
def __ror__(self, other: ColumnOrLiteral) -> Column:
return self.inverse_binary_op(exp.Or, other)
@classmethod
def ensure_col(cls, value: t.Optional[t.Union[ColumnOrLiteral, exp.Expression]]):
return cls(value)
@classmethod
def ensure_cols(cls, args: t.List[t.Union[ColumnOrLiteral, exp.Expression]]) -> t.List[Column]:
return [cls.ensure_col(x) if not isinstance(x, Column) else x for x in args]
@classmethod
def _lit(cls, value: ColumnOrLiteral) -> Column:
if isinstance(value, dict):
columns = [cls._lit(v).alias(k).expression for k, v in value.items()]
return cls(exp.Struct(expressions=columns))
return cls(exp.convert(value))
@classmethod
def invoke_anonymous_function(
cls, column: t.Optional[ColumnOrLiteral], func_name: str, *args: t.Optional[ColumnOrLiteral]
) -> Column:
columns = [] if column is None else [cls.ensure_col(column)]
column_args = [cls.ensure_col(arg) for arg in args]
expressions = [x.expression for x in columns + column_args]
new_expression = exp.Anonymous(this=func_name.upper(), expressions=expressions)
return Column(new_expression)
@classmethod
def invoke_expression_over_column(
cls, column: t.Optional[ColumnOrLiteral], callable_expression: t.Callable, **kwargs
) -> Column:
ensured_column = None if column is None else cls.ensure_col(column)
ensure_expression_values = {
k: [Column.ensure_col(x).expression for x in v]
if is_iterable(v)
else Column.ensure_col(v).expression
for k, v in kwargs.items()
}
new_expression = (
callable_expression(**ensure_expression_values)
if ensured_column is None
else callable_expression(
this=ensured_column.column_expression, **ensure_expression_values
)
)
return Column(new_expression)
def binary_op(self, klass: t.Callable, other: ColumnOrLiteral, **kwargs) -> Column:
return Column(
klass(this=self.column_expression, expression=Column(other).column_expression, **kwargs)
)
def inverse_binary_op(self, klass: t.Callable, other: ColumnOrLiteral, **kwargs) -> Column:
return Column(
klass(this=Column(other).column_expression, expression=self.column_expression, **kwargs)
)
def unary_op(self, klass: t.Callable, **kwargs) -> Column:
return Column(klass(this=self.column_expression, **kwargs))
@property
def is_alias(self):
return isinstance(self.expression, exp.Alias)
@property
def is_column(self):
return isinstance(self.expression, exp.Column)
@property
def column_expression(self) -> exp.Column:
return self.expression.unalias()
@property
def alias_or_name(self) -> str:
return self.expression.alias_or_name
@classmethod
def ensure_literal(cls, value) -> Column:
from sqlglot.dataframe.sql.functions import lit
if isinstance(value, cls):
value = value.expression
if not isinstance(value, exp.Literal):
return lit(value)
return Column(value)
def copy(self) -> Column:
return Column(self.expression.copy())
def set_table_name(self, table_name: str, copy=False) -> Column:
expression = self.expression.copy() if copy else self.expression
expression.set("table", exp.to_identifier(table_name))
return Column(expression)
def sql(self, **kwargs) -> str:
return self.expression.sql(**{"dialect": "spark", **kwargs})
def alias(self, name: str) -> Column:
new_expression = exp.alias_(self.column_expression, name)
return Column(new_expression)
def asc(self) -> Column:
new_expression = exp.Ordered(this=self.column_expression, desc=False, nulls_first=True)
return Column(new_expression)
def desc(self) -> Column:
new_expression = exp.Ordered(this=self.column_expression, desc=True, nulls_first=False)
return Column(new_expression)
asc_nulls_first = asc
def asc_nulls_last(self) -> Column:
new_expression = exp.Ordered(this=self.column_expression, desc=False, nulls_first=False)
return Column(new_expression)
def desc_nulls_first(self) -> Column:
new_expression = exp.Ordered(this=self.column_expression, desc=True, nulls_first=True)
return Column(new_expression)
desc_nulls_last = desc
def when(self, condition: Column, value: t.Any) -> Column:
from sqlglot.dataframe.sql.functions import when
column_with_if = when(condition, value)
if not isinstance(self.expression, exp.Case):
return column_with_if
new_column = self.copy()
new_column.expression.args["ifs"].extend(column_with_if.expression.args["ifs"])
return new_column
def otherwise(self, value: t.Any) -> Column:
from sqlglot.dataframe.sql.functions import lit
true_value = value if isinstance(value, Column) else lit(value)
new_column = self.copy()
new_column.expression.set("default", true_value.column_expression)
return new_column
def isNull(self) -> Column:
new_expression = exp.Is(this=self.column_expression, expression=exp.Null())
return Column(new_expression)
def isNotNull(self) -> Column:
new_expression = exp.Not(this=exp.Is(this=self.column_expression, expression=exp.Null()))
return Column(new_expression)
def cast(self, dataType: t.Union[str, DataType]):
"""
Functionality Difference: PySpark cast accepts a datatype instance of the datatype class
Sqlglot doesn't currently replicate this class so it only accepts a string
"""
if isinstance(dataType, DataType):
dataType = dataType.simpleString()
new_expression = exp.Cast(
this=self.column_expression,
to=sqlglot.parse_one(dataType, into=exp.DataType, read="spark"), # type: ignore
)
return Column(new_expression)
def startswith(self, value: t.Union[str, Column]) -> Column:
value = self._lit(value) if not isinstance(value, Column) else value
return self.invoke_anonymous_function(self, "STARTSWITH", value)
def endswith(self, value: t.Union[str, Column]) -> Column:
value = self._lit(value) if not isinstance(value, Column) else value
return self.invoke_anonymous_function(self, "ENDSWITH", value)
def rlike(self, regexp: str) -> Column:
return self.invoke_expression_over_column(
column=self, callable_expression=exp.RegexpLike, expression=self._lit(regexp).expression
)
def like(self, other: str):
return self.invoke_expression_over_column(
self, exp.Like, expression=self._lit(other).expression
)
def ilike(self, other: str):
return self.invoke_expression_over_column(
self, exp.ILike, expression=self._lit(other).expression
)
def substr(self, startPos: t.Union[int, Column], length: t.Union[int, Column]) -> Column:
startPos = self._lit(startPos) if not isinstance(startPos, Column) else startPos
length = self._lit(length) if not isinstance(length, Column) else length
return Column.invoke_expression_over_column(
self, exp.Substring, start=startPos.expression, length=length.expression
)
def isin(self, *cols: t.Union[ColumnOrLiteral, t.Iterable[ColumnOrLiteral]]):
columns = flatten(cols) if isinstance(cols[0], (list, set, tuple)) else cols # type: ignore
expressions = [self._lit(x).expression for x in columns]
return Column.invoke_expression_over_column(self, exp.In, expressions=expressions) # type: ignore
def between(
self,
lowerBound: t.Union[ColumnOrLiteral],
upperBound: t.Union[ColumnOrLiteral],
) -> Column:
lower_bound_exp = (
self._lit(lowerBound) if not isinstance(lowerBound, Column) else lowerBound
)
upper_bound_exp = (
self._lit(upperBound) if not isinstance(upperBound, Column) else upperBound
)
return Column(
exp.Between(
this=self.column_expression,
low=lower_bound_exp.expression,
high=upper_bound_exp.expression,
)
)
def over(self, window: WindowSpec) -> Column:
window_expression = window.expression.copy()
window_expression.set("this", self.column_expression)
return Column(window_expression)
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