List Operations
Here is a quick run-through of the operations you can do on lists:
A. Making lists:
L = [] (the empty list, which is the list with no elements)
L = [ abc, de, fghij, 1, [2, 3]}: this list has 5 elements: three strings, one integer and one list.
L = L1 + L2, where L1 and L2 are lists. This concatenates L1 and L2 into a new list L.
L = L1 * 3, where L1 is a list. This makes a new list L, which is the concatenation of L1 3 times, as in L1 + L1 + L1.
B. Indexing:
L[0]: the first element in list L
L[1]: the second element in list L
L[2:5]: a slice of
list L, which is a new list consisting of the elements at positions
2, 3, and 4 (but
not 5) of L.
C.
Changing the contents of the list, without changing the
list itself:
L[i] = a:
changes the value of the ith entry of L to a
L.append(x): adds x to the end of the list L
L.extend(L1): where L1 is a list. This adds all the entries of L1 onto L
L.sort(): sorts, or arranges in order, the entries of L
L.reverse(): reverses the order of the entries of L
L[i:j] = [] deletes the index i through j slice of L
D. Other stuff
len(L): the length, or number of entries, of L
for x in L: iterates a loop over all entries of L
x in L: returns True if L has an entry whose value is x
L.index(v): returns the index of the first entry of L that equals v; crashes if L does
not contain v