I have a problem to which I can not find a solution for more laps I give it. I have a program in which I generate a series of data and store them in a list. Later I have to remove some of the elements from the list so that its size is smaller. I always delete the first or last item in the list for which I use the "del" or "pop" functions.

To generate the list I want to work on, I call a function created by me that returns a list. Something like this:

```
y = generadatos(a1,a2,a3)
del y[0]
```

When it reaches the line with the "del" the program hangs. I tried to do it from the console by typing from and [0] and it gives me the following error:

ValueError: can not delete array elements

However, if I open a new sheet and I think this simple code works without problems:

```
a=[1,2,3,4]
del a[0]
print a
```

If instead of using "from" use "pop" the same thing happens. I thought that maybe the list that returns the function that generates the data does something that I do not understand and that's why it does not let me delete elements.

Any ideas?

Thank you very much.

Edit1:

The "generadatos" function is this:

```
def generadatos(nst,p0st,ast,lbst,timesstrst,pvst,incremst):
xbigst = 0
xsmallst = 0
I0bigst = []
I0smallst = []
for ist in range(0,nst+1):
pst = p0st + ast*ist
pbigst = np.abs((pst*pvst)/(pst-pvst))
psmallst = np.abs((pst*pvst)/(pst+pvst))
limitpbigst = pbigst/lbst
limitpbigst = np.int(limitpbigst)
halflimitpbigst = np.int(limitpbigst/2)
limitpsmallst = psmallst/lbst
limitpsmallst = np.int(limitpsmallst)
halflimitpsmallst = np.int(limitpsmallst/2)
for jst in range(0,timesstrst):
for kst in range(0,halflimitpbigst):
I0bigst.append(1)
xbigst = xbigst + 1
for lst in range(halflimitpbigst,limitpbigst):
I0bigst.append(0)
xbigst = xbigst + 1
for mst in range(0,halflimitpsmallst):
I0smallst.append(1)
xsmallst = xsmallst + 1
for ost in range(halflimitpsmallst,limitpsmallst):
I0smallst.append(0)
xsmallst = xsmallst + 1
limitpbig2st = np.int((pbigst/2)/lbst)
for qst in range (0,limitpbig2st):
del I0bigst[-1]
limitpsmall2st = np.int((psmallst/2)/lbst)
for rst in range (0,limitpsmall2st):
del I0smallst[-1]
if incremst > 0:
aux1st = I0bigst[::]
I0bigst = aux1st[::-1]
else:
aux1st = I0smallst[::]
I0smallst = aux1st[::-1]
I0st = np.append(I0smallst,I0bigst)
return I0st'
```

At first I create empty lists in the `I0 = []`

style.
Then I add data using 'I0.append (value)
And finally I use the NumPy function
I0st = np.append (I0smallst, I0bigst)

```
return I0st
```