[List] 자주쓰이는 리스트 메소드 정리

1. concatenate 

# 1. use + operation 
a = [1,2,3]
b = [4,5]

c = a+b # [1,2,3,4,5]

# 2. use .append method 
x = [1,2,3]
y = [4,5]
x.append(y) # [1,2,3,[4,5]]

# 3. use .extend method
x = [1,2,3]
y = [4,5]
x.extend(y) # [1,2,3,4,5]

 

2. delete the value 

l = [1,2,3,4,5]

# 1. using pop()
l.pop() # return 5, l=[1,2,3,4]

# 2. delete by index using .del method 
del(l[0]) #return None, l=[2,3,4,5]

# 3. delete by value using .remove method
l.remove(3) # return None, l=[1,2,4,5]

 

3. sort 

l = [3,7,-1,2]

# sort in place
l.sort()
print(l) # [-1,2,3,7]

# create new ordered array 
a = sorted(l)
print(l) # [3,7,-1,2]
print(a) # [-1,2,3,7]

#sort reverse order 
l.reverse() 
print(l) # [2,-1,7,3]