Question: Consider this example:

```
import numpy as np
a = np.array(1)
np.save("a.npy", a)

a = np.load("a.npy", mmap_mode='r')
print(type(a))

b = a + 2
print(type(b))

```

which outputs

```
<class 'numpy.core.memmap.memmap'>
<class 'numpy.int32'>

```

So it seems that `b` is not a `memmap` any more, and I assume that this forces `numpy` to read the whole `a.npy`, defeating the purpose of the memmap. Hence my question, can operations on `memmaps` be deferred until access time?

I believe subclassing `ndarray` or `memmap` could work, but don't feel confident enough about my Python skills to try it.

Here is an extended example showing my problem:

```
import numpy as np

# create 8 GB file
# np.save("memmap.npy", np.empty([1000000000]))

# I want to print the first value using f and memmaps

def f(value):
    print(value[1])

# this is fast: f receives a memmap
a = np.load("memmap.npy", mmap_mode='r')
print("a = ")
f(a)

# this is slow: b has to be read completely; converted into an array
b = np.load("memmap.npy", mmap_mode='r')
print("b + 1 = ")
f(b + 1)

```

Answer: 
You can use `nextTick` which will call a function after the next DOM update cycle.

```
this.datepicker = true;

Vue.nextTick(function () {
  $(".jquery-date-picker").datepicker();
})

```

And here is it's page in the documentation [VueJS Docs](https://v2.vuejs.org/v2/api/#Vue-nextTick)
Vue features triggers, in your case the `mounted()` function could be used. This articles describes how to use it and the whole Vue hook timeline : <https://alligator.io/vuejs/component-lifecycle/>

A stackoverflow explanation : [Vue JS mounted()](https://stackoverflow.com/q/45021907/7477557)