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 | 1 | initial version |
The method .reverse() reverses the list L on place (i mean it modifies the list L), it does not return a sorted copy of L (it returns nothing, hence your behaviour), but the list L itself is modified as you can check:
sage: L = [4,2,5,1,3] sage: L.reverse() sage: L [3, 1, 5, 2, 4]
| | 2 | No.2 Revision |
The method .reverse() reverses the list L on place (i mean it modifies the list L), it does not return a sorted copy of L (it returns nothing, hence your behaviour), but the list L itself is modified as you can check:
Now if you want to get a reversed copy of L without modifying L, you can use the reversed() function.
sage: L = [4,2,5,1,3]
sage: L2 = reversed(L)
sage: L2
<listreverseiterator at 0x65a5d50>
As you can see, it returns an iterator, not a list, it means that you can still play with it:
sage: for i in L2:
....: print i
....:
3
1
5
2
4
If you want to get a reversed list of L without modifying L you can transform the reversed iterator into a list:
sage: L = [4,2,5,1,3]
sage: L2 = list(reversed(L))
sage: L2
[3, 1, 5, 2, 4]
| | 3 | No.3 Revision |
The method .reverse() reverses the list L on place (i mean it modifies the list L), it does not return a sorted copy of L (it returns nothing, hence your behaviour), but the list L itself is modified as you can check:
sage: L = [4,2,5,1,3]
sage: L.reverse()
sage: L
[3, 1, 5, 2, 4]
Now if you want to get a reversed copy of L without modifying L, you can use the reversed() function.function:
sage: L = [4,2,5,1,3]
sage: L2 = reversed(L)
sage: L2
<listreverseiterator at 0x65a5d50>
As you can see, it returns an iterator, not a list, it means that you can still play with it:
sage: for i in L2:
....: print i
....:
3
1
5
2
4
If you want to get a reversed list of L without modifying L you can transform the reversed iterator into a list:
sage: L = [4,2,5,1,3]
sage: L2 = list(reversed(L))
sage: L2
[3, 1, 5, 2, 4]
| | 4 | No.4 Revision |
The method .reverse() reverses the list L on place (i mean it (it modifies the list L), as stated in the tutorial), it does not return a sorted reversed copy of L (it returns nothing, hence your behaviour), but the list L itself is modified as you can check:
sage: L = [4,2,5,1,3]
sage: L.reverse()
sage: L
[3, 1, 5, 2, 4]
Now if you want to get a reversed copy of L without modifying L, you can use the reversed() function:
sage: L = [4,2,5,1,3]
sage: L2 = reversed(L)
sage: L2
<listreverseiterator at 0x65a5d50>
As you can see, it returns an iterator, not a list, it means that you can still play with it:
sage: for i in L2:
....: print i
....:
3
1
5
2
4
If you want to get a reversed list of L without modifying L you can transform the reversed iterator into a list:
sage: L = [4,2,5,1,3]
sage: L2 = list(reversed(L))
sage: L2
[3, 1, 5, 2, 4]
| | 5 | No.5 Revision |
The method .reverse() reverses the list L on place (it modifies the list L as stated in the tutorial), it does not return a reversed copy of L (it returns nothing, hence your behaviour), but the list L itself is modified as you can check:
sage: L = [4,2,5,1,3]
sage: L.reverse()
sage: L
[3, 1, 5, 2, 4]
Now if you want to get a reversed copy of L without modifying L, you can use the reversed() function:
sage: L = [4,2,5,1,3]
sage: L2 = reversed(L)
sage: L2
<listreverseiterator at 0x65a5d50>
As you can see, it returns an iterator, not a list, it means that you can still play with it:it as if it was a list, but only once (the elements of L2 are thrown once used):
sage: for i in L2:
....: print i
....:
3
1
5
2
4
sage: for i in L2:
....: print i
....:
<nothing printed>
If you want to get a reversed list of L without modifying L you can transform the reversed iterator into a list:
sage: L = [4,2,5,1,3]
sage: L2 = list(reversed(L))
sage: L2
[3, 1, 5, 2, 4]
