Python基础 之 列表常用方法及技巧

'''列表'''
# 访问列表、索引从0开始
cars = ['audi', 'toyota', 'subaru', 'bmw']
print(cars[0])

# 修改、添加、删除列表元素
print(cars)
cars[2] = 'suv'
print(cars)
cars.remove('suv')
print(cars)
cars.append('suv')
cars.insert(2,'subaru')
print(cars)

# 列表排序： 永久sort，临时sorted,列表长度
print ('Here is the sorted list:')
print(sorted(cars))
print ('Here is the original list:')
print(cars)

copy_cars = cars.copy()
print ('Here is the copied list:')
print(copy_cars)
print ('Here is the original list:')
print(cars)

print ('Here is the sort-copy list:')
copy_cars.sort()
print(copy_cars)
print ('Here is the original list:')
print(cars)

listlength = len(cars)
print('here is the length of the list: %s'%listlength)

# 避免索引错误：
# print(cars[5])

'''range()'''
# range()函数创建数值列表：max，min，sum
squares = []
for i in range(1,11):
value = i**2
squares.append(value)
print(squares)

alist = ['a', 'b', 'c']
for i in range(0, len(alist)):
alist[i] = alist[i] + 'a'
print(alist)

# 列表解析：
squares = [value**2 for value in range(1,11)]
print(squares)

# 列表切片：
cars = [1,2,3,4,5,6]
car1 = cars[0:2]
car2 = cars[2:]
car3 = cars[:3]
car4 = cars[-3:]
print('original list is: %s' %cars)
print('0:2 list is: %s' %car1)
print('2: list is: %s' %car2)
print(':3 list is: %s' %car3)
print('-3: list is: %s' %car4)

# 复制列表与直接赋值不一样:
myfavor = ['pizza', 'sleep']
# myfriendfavor = myfavor[:] # 这种方式复制列表相当于将myfavor的副本存储到myfriendfavor，跟赋值不一样。
myfriendfavor = myfavor # 直接赋值相当于将变量myfriendfavor关联到包含在myfavor中的列表，这2个变量都指向同一个列表
myfavor.append('read')
myfriendfavor.append('study')

print(myfavor)
print(myfriendfavor)

lista = ['1','2']
listb = ['3','4']
mix = (lista, listb)
lista.append('null')
print(mix)
# for、while、if忘记缩进（额外的行）、遗漏冒号