Hi, here are common Pyton List Manipulation methods.
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In Python, List are a collection of items is particular order. You can put anything you want into a List.
By convention normally you will make the name your List plural. For example a list of person can be name people.
Python use square bracket [] to indicate a List, and individual elements are separated by commas.
List is zero base. That mean the first position is 0 and the second position is 1, etc.
# Create a list
fruits = ['orange', 'apple', 'melon']
# Accessing a List element
fruits[0] # first item
fruits[-1] # last item
# Append to List
fruits.append('banana')
# Insert to List at position x
fruits.insert(1, 'banana') # will be insert second in the List
# List length
nb_items = len(fruits) # 4
# Remove from list
del fruits[1] # remove apple
# Remove and return last element
lastFruit = fruits.pop() # remove last and return it's value into lastFruit
# Slice my_list[start:finish:step] ([::-1] reverse list)
fruits = fruits[1:3]
fruits[:3] # first 3
fruits[2:] # last 2
copy_fruits = fruits[:] # copy
#Create list from string
colors = 'red, green, blue'.split(', ')
#Reverse a List
colors.reverse()
# Array concact
color1 = ['red', 'blue']
color2 = ['green', 'yellow']
color3 = color1 + color2
# Concat by unpacking
color3 = [*color1, *color2]
# Multiple assignment
name, price = ['iPhone', 599]
#Create a Tuple (kind of read only list)
colors = ('red', 'green', 'blue')
# Sort
colors.sort() # ['blue', 'green', 'red']
colors.sort(reverse=True) # ['red', 'green', 'blue']
colors.sort(key=lambda color: len(color)) # ['red', 'blue', 'green']
# Looping in a List
for color in colors:
print(color)
# Generate a List of numbers
numbers = List(range(1, 10)) # 1 2 3 4 5 6 7 8 9
# List comprehension offers a shorter syntax when you want
# to create a new list based on the values of an existing list.
# Example of long version
fruits = ["apple", "banana", "cherry", "kiwi", "mango"]
newFruits = []
for x in fruits:
if "a" in x:
newFruits.append(x)
print(newFruits)
# Same example with List Comprehension
fruits = ["apple", "banana", "cherry", "kiwi", "mango"]
newFruits = [x for x in fruits if "a" in x]
# Syntax: [expression for item in iterable if condition == True]
print(newFruits)
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