Curious - 11 months ago 88

Python Question

Is there a quick way to "sub-flatten" or flatten only some of the first dimensions in a numpy array?

For example, given a numpy array of dimensions

`(50,100,25)`

`(5000,25)`

Thanks

Answer

Take a look at numpy.reshape .

```
>>> arr = numpy.zeros((50,100,25))
>>> arr.shape
# (50, 100, 25)
>>> new_arr = arr.reshape(5000,25)
>>> new_arr.shape
# (5000, 25)
# One shape dimension can be -1.
# In this case, the value is inferred from
# the length of the array and remaining dimensions.
another_arr = arr.reshape(-1, arr.shape[-1])
another_arr.shape
# (5000, 25)
```

Source (Stackoverflow)