Functions and methods of python (in)

anonymous function

1. What is an anonymous function

A lambda is an anonymous function and an expression, the smallest unit of combat of a function

Anonymous functions are, as the name suggests, "nameless" functions.

Anonymous functions for simple business logic

One function per line

In layman's terms, functions with uncomplicated logic that don't require large-scale bulk calls can be built using anonymous functions, which are written in a way that determines their simplicity.

#lambda is simple and uncomplicated

Note that lambda is a python keyword used to declare an anonymous function

** The difficulty of anonymous functions is not in their construction itself, but in their combinatorial use!

2. How to declare/call an anonymous function (lambda)

# Traditional functions:
def add(num1):
	return num1 * 2
call (programming)：add(2)
exports：4
def add(num1,num2):
	return num1 + num2
call (programming)：add(1,2)
exports：3
# anonymous function:
result = lambda x: x*2
call (programming)：result(2)
exports：4 
result = lambda x,y: x+y
call (programming)：result(x=1,y=2)
exports：3

3. Several ways to use anonymous functions

#1, anonymous function combining three-eye operations
traditional function
def compare(x,y):
	if x > y:
		return x
	else:
		return y
call (programming)：compare(2,1)
exports：2
anonymous function
compare = lambda x,y: x if x > y else y
call (programming)：compare(2,1)
exports：2

#2. pass lambda as a method into a traditional function
schools = ["Python Basics.",
		   "Python crawler.",
		   "Java Programming",
		   "Java Web",
		   "Python Data Analysis."
]
def keyword_serch(keys,func):
	search_result= []
	for result in keys:
		if func(result):
			search_result.append(result)
	return search_result
condition = lambda x: True if "Python" in x else False
invocations：keyword_serch(schools,condition)
exports： ["Python Basics.","Python crawler.","Python Data Analysis."]

#3: How to pass parameters to lambda in def function?
def main():
	return lambda x: True if x == 10 else False
			（in the event thatxbe tantamount to10Return to true，Otherwise false）
invocations：main()(10) 
	fulfillmentmainfunction (math.)，stillmainNo need to pass a parameter；
	The second bracket is then for thelambdatransmittedxspecifications
exports：True

#4. pass lambda as a method into a traditional function
def income(basic,transport,phone):
	return lambda x: x+basic+transport+phone
invocations：total = income（1000,2000,3000）
	 total(4000)
exports：10000
schools = ["Python Basics.",
		   "Python crawler.",
		   "Java Programming",
		   "Java Web",
		   "Python Data Analysis."
]
def keyword_search(keys,func):
	search_result= []
	for key in keys:
		if func(key):
			search_result.append(key)
	return search_result
def search_condition(c):
	return lambda x: True if c in x else False
python = search_condition("Python")
invocations：keyword_search(schools,python)
exports：["Python Basics.","Python crawler.","Python Data Analysis."]