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do python lambda expressions not qualify? https://docs.python.org/3/tutorial/controlflow.html#lambda-expressions https://docs.python.org/3/tutorial/controlflow

do python lambda expressions not qualify? https://docs.python.org/3/tutorial/controlflow.html#lambda-expressions https://docs.python.org/3/tutorial/controlflow.html#lambda-e...

ByteJockey 5y ago
Lambda expressions in python are limited to a single expression. The poster explicitly calls out wanting more than one line.
- mistaken 5y ago
  It's possible to execute statements in a lambda through exec. But it's more of hack than what it worth. print((lambda x: [exec('x = x + 1; result = x'), eval('result')][1])(1))
- vorticalbox 5y ago
  I don't understand why you wouldn't just define a function if you needed multi lines.
  - Chris_Newton 5y ago
    I don't understand why you wouldn't just define a function if you needed multi lines. For the same reason that you wouldn’t necessarily define a function every time you wanted more than one line in the body of an if statement or for loop. In a functional programming style, typically most of your control structures are represented as higher-order functions and you pass them other functions where you might use nested blocks of statements in an imperative style. That is, where imperative pseudocode might look like this: for n in [0..10]: output_array[n] = n * n some corresponding functional pseudocode might look more like this: output_array = for_each [0..10] (n -> n * n) In some functional languages, it’s even idiomatic to write the supporting function so it reads more like this (borrowing Haskell’s $ notation, which avoids the awkward parentheses): output_array = for_each [0..10] $ \n -> n * n Now you might want a multiline body for the supporting function in much the same situations that you might want a multiline body for the imperative for loop: for n in [0..10]: location = get_location(n) route = fastest_route_to(location) times[n] = average_journey_time(route) times = for_each [0..10] $ \n -> location = get_location(n) route = fastest_route_to(location) average_journey_time(route) Similarly, if the logic you’re using in the inner part of the code is a self-contained concept, you might want to factor it out into a named function of its own in either case. This functional style can be tidy and very flexible in languages that are designed to support it. However, I wouldn’t necessarily encourage it in a language like Python, precisely because Python’s syntax and language features don’t make it natural and concise to write like this.

do python lambda expressions not qualify? https://docs.python.org/3/tutorial/controlflow.html#lambda-expressions https://docs.python.org/3/tutorial/controlflow.html#lambda-e...

ByteJockey 5y ago

Lambda expressions in python are limited to a single expression. The poster explicitly calls out wanting more than one line.

mistaken 5y ago
It's possible to execute statements in a lambda through exec. But it's more of hack than what it worth. print((lambda x: [exec('x = x + 1; result = x'), eval('result')][1])(1))
vorticalbox 5y ago
I don't understand why you wouldn't just define a function if you needed multi lines.
- Chris_Newton 5y ago
  I don't understand why you wouldn't just define a function if you needed multi lines. For the same reason that you wouldn’t necessarily define a function every time you wanted more than one line in the body of an if statement or for loop. In a functional programming style, typically most of your control structures are represented as higher-order functions and you pass them other functions where you might use nested blocks of statements in an imperative style. That is, where imperative pseudocode might look like this: for n in [0..10]: output_array[n] = n * n some corresponding functional pseudocode might look more like this: output_array = for_each [0..10] (n -> n * n) In some functional languages, it’s even idiomatic to write the supporting function so it reads more like this (borrowing Haskell’s $ notation, which avoids the awkward parentheses): output_array = for_each [0..10] $ \n -> n * n Now you might want a multiline body for the supporting function in much the same situations that you might want a multiline body for the imperative for loop: for n in [0..10]: location = get_location(n) route = fastest_route_to(location) times[n] = average_journey_time(route) times = for_each [0..10] $ \n -> location = get_location(n) route = fastest_route_to(location) average_journey_time(route) Similarly, if the logic you’re using in the inner part of the code is a self-contained concept, you might want to factor it out into a named function of its own in either case. This functional style can be tidy and very flexible in languages that are designed to support it. However, I wouldn’t necessarily encourage it in a language like Python, precisely because Python’s syntax and language features don’t make it natural and concise to write like this.