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Here is what I am trying to do
class BaseClass(object):
successify = lambda x: "<Success>%s</Success>" % x
errorify = lambda x: "<Error>%s</Error>" % x
def try1(self):
print successify("try1")
def try2(self):
print self.successify("try2")
But neither of the methods seem to work..
>>> BaseClass().try1()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 5, in try1
NameError: global name 'successify' is not defined
>>> BaseClass().try2()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 7, in try2
TypeError: <lambda>() takes exactly 1 argument (2 given)
How do I use lambdas as methods within a class?
591
Syntax. Simply put, a lambda function is just like any normal python function, except that it has no name when defining it, and it is contained in one line of code. A lambda function evaluates an expression for a given argument. You give the function a value (argument) and then provide the operation (expression).
You can invoke a Lambda function by creating an AWSLambda object and invoking its invoke method. Create an InvokeRequest object to specify additional information such as the function name and the payload to pass to the Lambda function.
You can use lambda function in map() map() function applies a given function to all the itmes in a list and returns the result. Similar to filter() , simply pass the lambda function and the list (or any iterable, like tuple) as arguments.
Using lambdas with Python built-ins Lambda functions provide an elegant and powerful way to perform operations using built-in methods in Python. It is possible because lambdas can be invoked immediately and passed as an argument to these functions.
You have few possibilities of using/accessing class variables of lambdas. Three of them are:
class BaseClass(object):
successify = lambda x: "<Success>%s</Success>" % x
errorify = lambda x: "<Error>%s</Error>" % x
def try1(self):
print(self.__class__.successify("try1"))
def try2(self):
print(self.__class__.successify("try2"))
# or
class BaseClass(object):
successify = lambda x: "<Success>%s</Success>" % x
errorify = lambda x: "<Error>%s</Error>" % x
def try1(self):
print(BaseClass.successify("try1"))
def try2(self):
print(BaseClass.successify("try2"))
# or Please not changes to lambda definitions below
class BaseClass(object):
successify = lambda self,x: "<Success>%s</Success>" % x
errorify = lambda self,x: "<Error>%s</Error>" % x
def try1(self):
print(self.successify("try1"))
def try2(self):
print(self.successify("try2"))
Use lambda self, x: "...%s..." % x
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