KnowCardPython · lambda, Recursion & Built-in Functions
What does this print? ``` r = map(lambda x: x*2, [1, 2, 3]) print(len(r)) ```
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More in lambda, Recursion & Built-in Functions
A teammate wants a lambda that prints a value and returns it: lambda x: print(x); return x. Why won't this work?
You need to sort people by their age attribute. A colleague writes people.sort(lambda p: p.age). What's wrong?
What does this print?
```
funcs = [lambda: i
for i in range(3)]
print([f() for f in funcs])
```
In a loop you build callbacks with lambda: x and they all end up using the last value of x. What's the standard fix?
What does this print?
```
def fac(n):
if n > 1:
return fac(n-1) * n
return 1
print(fac(0))
```
A deep recursive function on a big input dies with RecursionError: maximum recursion depth exceeded. Why, and what's the usual fix?
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