More With Lists Strings Tuples Sets And Py Charm
More on Lists
Some more available operations:
ls3 = ls1 + ls2
concatenates lists and returns a new listls1.extend(ls2)
appends the values of a list to another listrepeated_ls = ls * 3
returns a new list with the sequence of values repeated x number of timesls[-1]
returns the value at the index oflen(ls) - 1
; useful for grabbing values at the end of the listls[start_index:end_index]
returns a slice of a list as a new liststart_index
is optional and is included in slice (defaults to0
if not included)end_index
is optional and is NOT included in slice (defaults tolen(ls)
if not included)Pro tip: A common way to create a copy of a list is via
ls[:]
Another pro tip: You can set values at multiple indices at once via...
ls[1:4] = [1,3, 5]
Two forms of equality testing:
Check for same reference:
ls1 is ls2
Check for same values:
ls1 == ls2
More on Strings
Think of strings like lists of characters. You can access characters at indices, except you just can't mutate them because strings are still immutable.
Instead, to mutate a character, a good technique is to convert to a list and then join
:
Note: join
takes the string as the separator and the list as the argument.
Just like a list, you can slice strings too:
Here's some useful string methods: see docs.
Tuples
Tuples are:
Sequence of values
Values do not have to be the same type
Immutable
Syntax for initializing tuple:
To access values in a tuple:
Pro tip: Tuples are very useful when returning multiple things from a function at once.
Sets
Sets are collections with the following features:
Unordered
Do not contain indices
Do not allow repeated elements
Values do not have to be the same type
Mutable
Syntax for initializing a set:
Operations for sets:
Iteration:
for item in set:
Adding element:
set.add("hello")
Removing element:
set.remove("goodbye")
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