root - 1 year ago 153

Python Question

I was writing some lambda functions and couldn't figure this out. Is there a way to have something like

`lambda x: x if (x<3)`

`lambda a,b: a if (a > b) else b`

`lambda x: x < 3 and x or None`

Answer Source

A lambda, like any function, must have a return value.

`lambda x: x if (x<3)`

does not work because it does not specify what to return if not `x<3`

. By default functions return `None`

, so you could do

```
lambda x: x if (x<3) else None
```

But perhaps what you are looking for is a list comprehension with an `if`

condition. For example:

```
In [21]: data = [1, 2, 5, 10, -1]
In [22]: [x for x in data if x < 3]
Out[22]: [1, 2, -1]
```