Difference between Python lambda and Python def, pythonlambda

Difference between Python lambda and Python def, pythonlambda

Python supports an interesting syntax that allows you to quickly define the smallest function of a single row. These lambda functions are borrowed from Lisp and can be used wherever functions are needed.

Lambda syntax is often confusing. What is lambda And why must lambda be used?

>>> def f(x):...   return x+2...>>> f(1)3>>> f = lambda x:x+2>>> f(1)3>>> (lambda x:x+2)(1)3

Python def and Python lambda have similarities and differences.
Similarities: These two important similarities are that you can define some fixed methods or flows to be called by the program. For example, you can define a variable plus 2 in the preceding example. The output result is 3. If you want to complete some fixed procedures, you can choose any of the above.

Which of the following are the same points?
Their main difference is that Python def is a statement while Python lambda is an expression. Lambda simplifies the writing of function definitions and simplifies the code. However, the function definition method is more intuitive and easy to understand.

Statements in Python can be nested. For example, if you need to define a method based on a certain condition, you can only use def. If lambda is used, an error is reported.

>>> if a==1:...   def info():...     print '1'*5... else:...   def info2():...     print 'info2'

Sometimes, when you need to operate in a python expression, you need to use expression nesting. In this case, Python def cannot get the desired result. You can only use Python lambda, as shown in the following example:
The most frequently-occurring letters of the Output e string:

>>> str='www.linuxeye.com linuxeye.com'>>> L = ([(i,str.count(i)) for i in set(str)])[(' ', 1), ('c', 2), ('e', 4), ('i', 2), ('m', 2), ('l', 2), ('o', 2), ('n', 2), ('u', 2), ('w', 3), ('y', 2), ('x', 2), ('.', 3)]>>> L.sort(key = lambda k:k[1],reverse = True)>>> print L[0][0]e