How to cut elements from list of integer

Question

if I have a list of integer

    x=[0, 0, 119, 101, 108, 108, 99, 111, 109]

I'd like to cut 2 elements from left

    x=[119, 101, 108, 108, 99, 111, 109]

What shall I do ?

Answer 1

Use Python's slice notation:

>>> x = [0, 0, 119, 101, 108, 108, 99, 111, 109]
>>> x = x[2:]
>>> x
[119, 101, 108, 108, 99, 111, 109]

This gets every element from the third item to the end of the list, and we just make x the value of that.

Answer 2

Nein nein nein

Sorry, I don't think that Haidro's solution to be good because a reassignation is performed that isn't necessary.

See:

x = [0, 0, 119, 101, 108, 108, 99, 111, 109]
print id(x)
x = x[2:]
print id(x)

print

y = [0, 0, 119, 101, 108, 108, 99, 111, 109, 1003]
print id(y)
y[:2] = []
print id(y)

result

18713576
18739528

18711736
18711736

EDIT 1

Showing an example of x = x[2:] causing an issue:

x = [0, 0, 119, 101, 108, 108, 99, 111, 109, 1003]
print id(x),x

gen = ((i,a+100) for i,a in enumerate(x))

for u in xrange(4):
    print '%d %d' % gen.next()

x = x[2:]
print 'x = x[2:]\n',id(x),x

for u in xrange(4):
    print '%d %d' % gen.next()

print '--------------------------'

y = [0, 0, 119, 101, 108, 108, 99, 111, 109, 1003]
print id(y),y

gen = ((i,b+100) for i,b in enumerate(y))

for u in xrange(4):
    print '%d %d' % gen.next()

y[:2] = []
print 'y[:2] = []\n',id(y),y

for u in xrange(4):
    print '%d %d' % gen.next()

result

18713576 [0, 0, 119, 101, 108, 108, 99, 111, 109, 1003]
0 100
1 100
2 219
3 201
x = x[2:]
18711736 [119, 101, 108, 108, 99, 111, 109, 1003]
4 208
5 208
6 199
7 211
--------------------------
18740128 [0, 0, 119, 101, 108, 108, 99, 111, 109, 1003]
0 100
1 100
2 219
3 201
y[:2] = []
18740128 [119, 101, 108, 108, 99, 111, 109, 1003]
4 199
5 211
6 209
7 1103

In the first case ( x = x[2:] ) , x is reassigned to another object. But the generator created before the reassignement still uses the same list object to yield elements. This may be an issue in certain codes.
But it's true that the other code could also be an issue in other cases.
What I mean is that we aren't protected from x = x[2:] to cause an issue, in the absolute.

EDIT 2

z[:] = z[2:] is notably different from y[:2] = [] :

import dis

print 'y[:2] = []'
def f(z):
    y[:2] = []
dis.dis(f)
print '====================='
print 'z[:] = z[2:]'
def f(z):
    z[:] = z[2:]
dis.dis(f)

result

y[:2] = []
  7           0 BUILD_LIST               0
              3 LOAD_GLOBAL              0 (y)
              6 LOAD_CONST               1 (2)
              9 STORE_SLICE+2       
             10 LOAD_CONST               0 (None)
             13 RETURN_VALUE        
=====================
z[:] = z[2:]
 12           0 LOAD_FAST                0 (z)
              3 LOAD_CONST               1 (2)
              6 SLICE+1             
              7 LOAD_FAST                0 (z)
             10 STORE_SLICE+0       
             11 LOAD_CONST               0 (None)
             14 RETURN_VALUE