If your array is called `a`

, the number of elements fulfilling `25 < x < 100`

is

```
((25 < a) & (a < 100)).sum()
```

The expression `(25 < a) & (a < 100)`

results in a Boolean array with the same shape as `a`

with the value `True`

for all elements that satisfy the condition. Summing over this Boolean array treats `True`

values as `1`

and `False`

values as `0`

.