036 for loop tủ tài liệu training

for Loops for loops is a type of loop that allows us walking on the lists, tuples, strings, and even dictionaries The syntax of this loop is: for item in object(it can be a list, a tuple, a dictionary etc.): statements Here is a breakdown of the syntax: for➜ the keyword that indicates that the for statement begins item ➜ specifies the name of the variable that will hold a single element of a sequence in ➜ indicates that the sequence comes next object ➜ the sequence that will be stepped through statements ➜ the statements that will be executed in each iteration Walking on the lists: In [1]: my_list = [1,2,3,4,5,6] for element in my_list: print("Item",element) Item Item Item Item Item Item In [2]: # Adding elements using for loop list1 = [1,2,3,4,5,6] sum = for item in list1: sum = sum + item print("Sum =",sum) Sum = 21 The Complete Python Programming Course: (Beginner to Advanced) In [3]: # Printing even numbers list2 = [1,2,3,4,5,6,7,8] for item in list2: if item % == 0: print(item) In [4]: # Printing odd numbers list2 = [1,2,3,4,5,6,7,8] for item in list2: if item % == 1: print(item) Walking on the strings: In [5]: s = "Hello world!" for letter in s: print(letter) H e l l o w o r l d ! In [6]: # Replicate strings using loops s = "Python" for letter in s: print(letter * 5) PPPPP yyyyy ttttt hhhhh ooooo nnnnn The Complete Python Programming Course: (Beginner to Advanced) Walking on the tuples: In [7]: # Walking on the tuples t = (1,2,3,4,5,6) for item in t: print(item) We can walkthrough the multidimensional tuples like this: In [8]: # Two-dimensional tuples list3 = [(1,2),(3,4),(5,6),(7,8)] for item in list3: print(item) (1, (3, (5, (7, 2) 4) 6) 8) We can see that each element is printed as tuple What if we want to reach that items? In [9]: # Tuple unpacking list3 = [(1,2),(3,4),(5,6),(7,8)] for (i,j) in list3: print("i:",i,"j:",j) i: i: i: i: j: j: j: j: In [10]: #Unpacking three dimensional tuples list4 = [(1,2,3),(4,5,6),(7,8,9),(10,11,12)] for (i,j,k) in list4: print(i * j * k) 120 504 1320 Walk through the dictionaries: We have learned methods of the dictionaries in our dictionaries lesson 1) keys() method 2) values() method 3) items() method The Complete Python Programming Course: (Beginner to Advanced) In [11]: my_dict = {"one":1,"two":2,"three":3,"four":4} my_dict.keys() Out[11]: dict_keys(['one', 'two', 'three', 'four']) In [12]: my_dict.values() Out[12]: dict_values([1, 2, 3, 4]) In [13]: my_dict.items() Out[13]: dict_items([('one', 1), ('two', 2), ('three', 3), ('four', 4)]) We can walk through the dictionaries with using these methods If we don't write any dict methods, we get keys of the dictionary as default Let's see this: In [14]: dict1 = {"one":1,"two":2,"three":3,"four":4} for i in dict1: print(i) one two three four In [15]: #using keys method dict1 = {"one":1,"two":2,"three":3,"four":4} for i in dict1.keys(): print(i) one two three four In [16]: #using values method dict1 = {"one":1,"two":2,"three":3,"four":4} for i in dict1.values(): print(i) In [17]: #using items method dict1 = {"one":1,"two":2,"three":3,"four":4} for i in dict1.items(): print(i) ('one', 1) ('two', 2) ('three', 3) ('four', 4) The Complete Python Programming Course: (Beginner to Advanced) In [18]: #getting the keys and values with items() dict1 = {"one":1,"two":2,"three":3,"four":4} for k,v in dict1.items(): print("Key:",k,"Value:",v) Key: Key: Key: Key: one Value: two Value: three Value: four Value: This is the end of this lesson See you in our next lessons In [ ]: The Complete Python Programming Course: (Beginner to Advanced) ... on the strings: In [5]: s = "Hello world!" for letter in s: print(letter) H e l l o w o r l d ! In [6]: # Replicate strings using loops s = "Python" for letter in s: print(letter * 5) PPPPP yyyyy... Printing even numbers list2 = [1,2,3,4,5,6,7,8] for item in list2: if item % == 0: print(item) In [4]: # Printing odd numbers list2 = [1,2,3,4,5,6,7,8] for item in list2: if item % == 1: print(item)... tuples t = (1,2,3,4,5,6) for item in t: print(item) We can walkthrough the multidimensional tuples like this: In [8]: # Two-dimensional tuples list3 = [(1,2),(3,4),(5,6),(7,8)] for item in list3: print(item)