List, Tuple, Dictionaries and Loops.md

📃LIST IN PYTHON

Syntax: l=[a1,a2,a3,....,an]

• Elements in a list are enclosed using '[]' paranthesis.
• Mutable data structure
• Duplicate values are allowed

🏗️List Constructer

Instead of using '[ ]' you can also implement a list using a list constructor.

                             list()

eg: countries= list(('Nigeria',34,False))

🎯List methods

  list1= [1,2,3,4,5]
  list2=['banana','apples','mango','oranges']

1. .extend() : combines elements of list1 with list2.

   Syntax: list1.extend(list2)
   

2. .append() : A pre-defined method used to add a single item to certain collection types(here: list).

   syntax: list.append('element')
   

3. .insert() : To insert an element to a specified index

   syntax: list2.insert(1,'cherry')
   

4. .remove() : To remove an element from the list.

   syntax: list2.remove('banana')
   

5. .clear() : empties a list

   syntax: list.clear()
   

6. .index()

    syntax: print(list.index("mango"))
   

7. .count()

   print(list.count(mango))
   

8. .sort() : prints list in ascending order

   syntax: list.sort()
   

9. .reverse() : prints contents of a list in reverse order

   syntax: list.reverse()
   

10. .copy() : used to copy contents from list to a new list.

syntax: list3= list2.copy()

11. .pop() : pops the last value of the list

syntax: list.pop()

pop(i) deletes the element in the specified index 'i' 12) del : used to delete the value with a specified index or a complete list

syntax: del list[0]

🔢Tuple

Syntax: t=(a1,a2,a3,....,an)

-Tuples are similar to lists -but they are immutable, meaning their elements cannot be changed after they are created. -Tuples are denoted by parentheses (). -It allows repetition of values.

eg: number=(1,'home','True',3,1)

👷🏿‍♀️Tuple Constructor

Adds 'tuple' as prefix and use 2 brackets.

t= tuple((1,'home','True',3,1))

📖Dictionary

Syntax: t={'a':1,'b':2,'c':3}

-Dictionaries are collections of key-value pairs. -Each key-value pair maps the key to its corresponding value. -Dictionaries are unordered, mutable, and indexed. -They are denoted by curly braces {}.

eg: d = {'a': 1, 'b': 2, 'c': 3}

Loops

While loop

it allows you to loop through a block of code , while a certain condition is true.

i=1
while<6
 print(i)
 i+=1

for loop

it is used for iterating over a sequence. syntax references :

1. String

   for i in hello:
     print(i)
   

2)List

mylist=['ji','ju','jo']
for i in mylist:
   print(i)

3)Dictionary

mydict={'name':'john','age':13,}
for i in mydict:
  print(i)