python if condition and "and"

Question

``` >>> def foo(a): print "called the function" if(a==1): return 1 else: return None >>> a=1 >>> if(foo(a) != None and foo(a) ==1): print "asdf" called the function called the function asdf ``` Hi. how can i avoid calling the function twice without using an extra variable.

Accepted Answer

You can chain the comparisons like this

```
if None != foo(a) == 1:
```

This works like

```
if (None != foo(a)) and (foo(a) == 1):
```

except that it only evaluates foo(a) once.

python if condition and "and"

Solution

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