Advantages And Disadvantages Of Lambda Expressions In Python And Their Usage Scenarios

Lambda expressions are a special syntax in Python for creating anonymous functions. We call the lambda syntax itself a lambda expression, and the function it returns is called a lambda function or anonymous functions. Python’s lambda expressions allow a function to be created and passed in one line of code, let us look at below source code.

website = ["www.pythontab.com", "bbs.pythontab.com", "docs.pythontab.com"]
def wordCount(string):
      return len(string)
siteNameLength = map(wordCount, website)
print(siteNameLength)

Below are the execution result.

[17, 17, 18]

The above code can be converted to a lambda expression as below.

website = ["www.pythontab.com", "bbs.pythontab.com", "docs.pythontab.com"]
siteNameLength = map(lambda string: len(string), website)
print(siteNameLength)

Below are the execution result.

[17, 17, 18]

Lambda expressions are just a special way to create functions. They contain only one statement and automatically return the result of that statement. When experienced Python programmers see a lambda expression, they know they are using a function that only works in one place and doing one thing.

1. Advantages And Disadvantages Of Lambda.

As you can see from the above example, lambda expressions can write very concise code, but the disadvantages are also obvious: they are difficult to understand and reduce readability and performance. Especially if you’re new to Python.

Let us look at a lambda expression below which is difficult to understand in short time.

lambda_list = lambda n: lambda_list(n-1) + (lambda x: x * (n-1),) if n else ()

1.1 Lambda Disadvantages.

  1. Lambda expressions are a strange and unfamiliar syntax to many Python programmers.
  2. Lambda functions themselves lack names and documentation, meaning that the only way to know what they do is to read the code.
  3. Lambda expressions can only contain one statement, so some readable language features, such as tuple unpacking, cannot be used with them.
  4. Lambda functions can often be replaced with existing functions in the standard library or Python built-in functions.

1.2 Lambda Advantages.

  1. The code is simple and clear.
  2. No additional variables are added.

2. Major Differences Between Lambda Expressions And Named Functions.

  1. Can be passed immediately (without variables).
  2. Only one line of code can be included internally.
  3. Automatic return of results.
  4. There is neither a document string nor a name.

3. Lambda Usage Scenarios.

The following scenario is suitable for lambda expressions.

  1. What you need to do is unimportant: functions don’t need a name.
  2. Using lambda expressions makes the code more easier to understand than the function name which you can think of.
  3. You’re pretty sure that there’s not a function that meets your needs.
  4. Everyone on your team knows lambda expressions and agrees to use it.

But lambda is not recommended unless you know what you’re doing. In team development, a good and easy-to-read code is very important to improve the efficiency of team collaborative development and reduce communication and maintenance costs.