def __init__(self, *args):
Guard.against_empty(
args,
"In order to create a new attribute expression you need to provide some attributes."
)
self.attributes = []
self.add_attributes(args)
def parse_avg(self, query, column):
seq = self.parse_select_many(query)
if len(seq) == 0:
return 0
error_message = (
"The attribute '%s' was not found in the specified collection's items. If you meant to use the raw value of each item in the collection just use the word 'item' as a parameter to .avg or use .avg()"
% column
)
Guard.against_empty(column, error_message)
attribute = column.replace("item.", "")
if "item." in column:
try:
seq = [self.rec_getattr(item, attribute) for item in seq]
except AttributeError:
raise ValueError(error_message)
else:
if attribute.lower() != "item":
raise ValueError(error_message)
return reduce(operator.add, seq) / len(seq)
def select(self, *cols):
empty_message = "Selecting with no fields is not valid. " \
+ "When using From(provider).select method, " \
+ "please provide a list of expressions or strings as fields."
Guard.against_empty(cols, empty_message)
for col in cols:
Guard.against_empty(col, empty_message)
Guard.accepts_only(cols, [str, Expression], "Selecting with invalid type. " \
+ "When using From(provider).select method, " \
+ "please provide a list of expressions or strings as fields.")
return self.provider.parse(self, action=Actions.Select, cols=cols)
def select(self, *cols):
empty_message = "Selecting with no fields is not valid. " \
+ "When using From(provider).select method, " \
+ "please provide a list of expressions or strings as fields."
Guard.against_empty(cols, empty_message)
for col in cols:
Guard.against_empty(col, empty_message)
Guard.accepts_only(cols, [str, Expression], "Selecting with invalid type. " \
+ "When using From(provider).select method, " \
+ "please provide a list of expressions or strings as fields.")
return self.provider.parse(self, action=Actions.Select, cols=cols)
def __init__(self, node_type, rhs):
'''Initializes the UnaryExpression with the specified arguments.
Arguments:
node_type - Specifies the type of operation that this UnaryExpression represents
rhs - Right-hand site of the operation. Since this is an unary operation, this is the only argument.
'''
Guard.against_empty(node_type, "The UnaryExpression node type is required")
if node_type == self.CollectionLength:
Guard.accepts(rhs, (ConstantExpression,), "The CollectionLength unary expression can only take ConstantExpressions that hold tuples or lists as parameters.")
if not isinstance(rhs.evaluate(), (list, tuple)):
raise ValueError("The CollectionLength unary expression can only take ConstantExpressions that hold tuples or lists as parameters.")
self.node_type = node_type
self.rhs = rhs
def __init__(self, node_type, lhs, rhs):
'''Initializes the BinaryExpression with the specified arguments.
Arguments:
node_type - Specifies the type of operation that this BinaryExpression represents
lhs - Left-hand side of the operation (as in the first argument)
rhs - Right-hand site of the operation (as in the second argument)
'''
Guard.against_empty(node_type, "The BinaryExpression node type is required")
Guard.accepts(lhs, (Expression,), "Lhs must be an expression (an instance of a class that inherits from pynq.Expression), but was %s" % lhs.__class__.__name__)
Guard.accepts(rhs, (Expression,), "Rhs must be an expression (an instance of a class that inherits from pynq.Expression) but was %s" % rhs.__class__.__name__)
self.node_type = node_type
self.lhs = lhs
self.rhs = rhs
def __init__(self, node_type, rhs):
'''Initializes the UnaryExpression with the specified arguments.
Arguments:
node_type - Specifies the type of operation that this UnaryExpression represents
rhs - Right-hand site of the operation. Since this is an unary operation, this is the only argument.
'''
Guard.against_empty(node_type,
"The UnaryExpression node type is required")
if node_type == self.CollectionLength:
Guard.accepts(
rhs, (ConstantExpression, ),
"The CollectionLength unary expression can only take ConstantExpressions that hold tuples or lists as parameters."
)
if not isinstance(rhs.evaluate(), (list, tuple)):
raise ValueError(
"The CollectionLength unary expression can only take ConstantExpressions that hold tuples or lists as parameters."
)
self.node_type = node_type
self.rhs = rhs
def __init__(self, node_type, lhs, rhs):
'''Initializes the BinaryExpression with the specified arguments.
Arguments:
node_type - Specifies the type of operation that this BinaryExpression represents
lhs - Left-hand side of the operation (as in the first argument)
rhs - Right-hand site of the operation (as in the second argument)
'''
Guard.against_empty(node_type,
"The BinaryExpression node type is required")
Guard.accepts(
lhs, (Expression, ),
"Lhs must be an expression (an instance of a class that inherits from pynq.Expression), but was %s"
% lhs.__class__.__name__)
Guard.accepts(
rhs, (Expression, ),
"Rhs must be an expression (an instance of a class that inherits from pynq.Expression) but was %s"
% rhs.__class__.__name__)
self.node_type = node_type
self.lhs = lhs
self.rhs = rhs
def parse_avg(self, query, column):
seq = self.parse_select_many(query)
if len(seq) == 0:
return 0
error_message = "The attribute '%s' was not found in the specified collection's items. If you meant to use the raw value of each item in the collection just use the word 'item' as a parameter to .avg or use .avg()" % column
Guard.against_empty(column, error_message)
attribute = column.replace("item.", "")
if "item." in column:
try:
seq = [self.rec_getattr(item, attribute) for item in seq]
except AttributeError:
raise ValueError(error_message)
else:
if attribute.lower() != "item":
raise ValueError(error_message)
return reduce(operator.add, seq) / len(seq)
def __perform_operation_on_all(self, query, column, operation,
command_name):
seq = self.parse_select_many(query)
if len(seq) == 0:
return 0
error_message = "The attribute '%s' was not found in the specified collection's items. If you meant to use the raw value of each item in the collection just use the word 'item' as a parameter to .%s or use .%s()" % (
column, command_name, command_name)
Guard.against_empty(column, error_message)
attribute = column.replace("item.", "")
if "item." in column:
try:
seq = [self.rec_getattr(item, attribute) for item in seq]
except AttributeError:
raise ValueError(error_message)
else:
if attribute.lower() != "item":
raise ValueError(error_message)
return operation(seq)
def __perform_operation_on_all(self, query, column, operation, command_name):
seq = self.parse_select_many(query)
if len(seq) == 0:
return 0
error_message = (
"The attribute '%s' was not found in the specified collection's items. If you meant to use the raw value of each item in the collection just use the word 'item' as a parameter to .%s or use .%s()"
% (column, command_name, command_name)
)
Guard.against_empty(column, error_message)
attribute = column.replace("item.", "")
if "item." in column:
try:
seq = [self.rec_getattr(item, attribute) for item in seq]
except AttributeError:
raise ValueError(error_message)
else:
if attribute.lower() != "item":
raise ValueError(error_message)
return operation(seq)
def do(self, a):
Guard.against_empty(a)
pass
def do(self, a):
Guard.against_empty(a, "Argument a is required")
pass
def do(self, a):
Guard.against_empty(a)
pass
def do(self, a):
Guard.against_empty(a, "Argument a is required")
pass
def __init__(self, *args):
Guard.against_empty(args, "In order to create a new attribute expression you need to provide some attributes.")
self.attributes = []
self.add_attributes(args)
