Following are some of the functions used formarly in this course:
Let's learn a few more:
Get index in a list: ?
Reversing a list: ?
Note: all the data structures in python are called
Python has built-in methods which informaly are:
Functions that belong to
python objects, e.g. A python object of type
methods, such as:
objects of type
float have "specific methods" depending on the
object.method_name( <arguments> )
address off operatorwhich uses
referenceof specified method to be searched from the standard library of python, which contains list of functions and methods.
To sum things up:
In Python, everything is an
object, and each object has a
specific method associated with it, depending on the
type of object.
objectsthey are called on.
1. String Methods -- 100xp, status: earned
In :""" Instructions: + Use the upper() method on room and store the result in room_up. Use the dot notation. + Print out room and room_up. Did both change? + Print out the number of o's on the variable room by calling count() on room and passing the letter "o" as an input to the method. - We're talking about the variable room, not the word "room"! """ # string to experiment with: room room = "poolhouse" # Use upper() on room: room_up room_up = room.upper() # Print out room and room_up print(room) print( "\n" + room_up ) # Print out the number of o's in room print("\n" + str( room.count("o") ) )
poolhouse POOLHOUSE 3
2. List Methods -- 100xp, status: earned
Other Python data types alos have many common method's associated with them, some of these methods are exclusive to some data types.
A few of them we will be experimenting on them:
index(), to get the index of the first element of a slist that matches its input.
count(), to get the number of times an element appears in a list.
In :""" Instructions: + Use the index() method to get the index of the element in areas that is equal to 20.0. Print out this index. + Call count() on areas to find out how many times 14.5 appears in the list. Again, simply print out this number. """ # first let's look more about these methods help(str.count) print(2*"\n===================================================") help(str.index) # Create list areas areas = [11.25, 18.0, 20.0, 10.75, 9.50] # Print out the index of the element 20.0 print( "\nThe index of the element 20.0 is: " + str( areas.index( 20 ) ) ) # Print out how often 14.5 appears in areas print("\nThe number of times 14.5 occurs is: " + str( areas.count( 14.5 ) ) )
Help on method_descriptor: count(...) S.count(sub[, start[, end]]) -> int Return the number of non-overlapping occurrences of substring sub in string S[start:end]. Optional arguments start and end are interpreted as in slice notation. =================================================== =================================================== Help on method_descriptor: index(...) S.index(sub[, start[, end]]) -> int Like S.find() but raise ValueError when the substring is not found. The index of the element 20.0 is: 2 The number of times 14.5 occurs is: 0
3. List Methods II -- 100xp, status: earned
Most list methods will change the list they're called on. E.g.
append(): adds and element to the list it is called on.
remove(): removes the "1st element" of a list that matches the inuput.
reverse(): reverse the order of the elements in the list it is called on.
In :""" Instructions: + Use the append method twice to add the size of the poolhouse and the garage again: - 24.5 and 15.45, respectively. - Add them in order + Print out the areas. + Use the reverse() method to reverse the order of the elements in areas. + Print out the area once more. """ # Let's look at the help on these methods help( list.append ) print("=====================================================") help( list.remove ) print("=====================================================") help( list.reverse )
Help on method_descriptor: append(...) L.append(object) -> None -- append object to end ===================================================== Help on method_descriptor: remove(...) L.remove(value) -> None -- remove first occurrence of value. Raises ValueError if the value is not present. ===================================================== Help on method_descriptor: reverse(...) L.reverse() -- reverse *IN PLACE*
In :# Create list areas areas = [11.25, 18.0, 20.0, 10.75, 9.50] # Use append twice to add poolhouse and garage size areas.append( 24.5 ) areas.append( 15.45 ) # Print out areas print("\nThe new list contains two new items: " + str( areas ) ) # Reverse the orders of the elements in areas areas.reverse() # Print out areas print("\nThe new list has been reversed: " + str( areas ) )
The new list contains two new items: [11.25, 18.0, 20.0, 10.75, 9.5, 24.5, 15.45] The new list has been reversed: [15.45, 24.5, 9.5, 10.75, 20.0, 18.0, 11.25]