Python Arrays






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Python Arrays



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Arrays


Arrays are used to store multiple values in one single variable:



Example


Create an array containing car names:



cars = ["Ford", "Volvo", "BMW"]

Run example »




What is an Array?


An array is a special variable, which can hold more than one value at a time.


If you have a list of items (a list of car names, for example), storing the
cars in single variables could look like this:





car1 = "Ford";
car2 = "Volvo";
car3 = "BMW";



However, what if you want to loop through the cars and find a specific one?
And what if you had not 3 cars, but 300?


The solution is an array!


An array can hold many values under a single name, and you can
access the values by referring to an index number.




Note: Python does not have built-in support for Arrays,
but Python lists can be used instead.






Access the Elements of an Array




You refer to an array element by referring to the index number.



Example


Get the value of the first array item:



x = cars[0]

Run example »



Example


Modify the value of the first array item:



cars[0] = "Toyota"

Run example »




The Length of an Array



Use the len() method to return the length of
an array (the number of elements in an array).




Example


Return the number of elements in the cars
array:



x = len(cars)

Run example »



Note: The length of an array is always one more than the highest array index.









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Looping Array Elements



You can use the for in loop to loop through all the elements of an array.



Example


Print each item in the cars array:



for x in cars:
  print(x)

Run example »




Adding Array Elements



You can use the append() method to add an element to an array.



Example


Add one more element to the cars array:



cars.append("Honda")

Run example »




Removing Array Elements



You can use the pop() method to remove an element from the array.



Example


Delete the second element of the cars array:



cars.pop(1)

Run example »


You can also use the remove() method to remove an element from the array.



Example


Delete the element that has the value "Volvo":



cars.remove("Volvo")

Run example »


Note: The remove() method
only removes the first occurrence of the specified value.






Array Methods


Python has a set of built-in methods that you can use on lists/arrays.




















































MethodDescription
append()Adds an element at
the end of the list
clear()Removes all the
elements from the list
copy()Returns a copy of the
list
count()Returns the number of
elements with the specified value
extend()Add the elements of a
list (or any iterable), to the end of the current list
index()Returns the index of
the first element with the specified value
insert()Adds an element at
the specified position
pop()Removes the element at the
specified position
remove()Removes the first
item with the specified value
reverse()Reverses the order
of the list
sort()Sorts the list


Note: Python does not have built-in support for Arrays,
but Python Lists can be used instead.







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