十、列表

1. 列表搜索 .index()

list=["1","2","3","4","5"]
list.index("3")  # 搜索3的位置

2

2. 列表的开始、结束、和步长值

• 用于列表开始、结束和步长值在“[ ]”里指定，相互之间用冒号“：”字符串分隔
  [star:stop:step]

• star：如果没有指定开始值，默认为0

• stop：如果没有指定结束值，则取列表中允许的最大值

• step：如果没有指定步长值，默认为1

number=["1","3","5","7","9"]
print(number[0:4:3])  # 每隔3个选择1个，0也可以不写

['1', '7']

number=["1","3","5","7","9"]
print(number[:4:3])

['1', '7']

number=["1","3","5","7","9"]
print(number[-1])  # 负数，取最后一个值

9

3. 列表的增、改、删

增

• i .append() 增加数据且增加在最后面
• ii .insert() 增加数据且可指定位置

number=["1","2","3"]
number.append("4")
print(number)

['1', '2', '3', '4']

number=["1","2","3"]
number.insert(1,"9")   # 在1的索引值那里添加“9”
print(number)

['1', '9', '2', '3']

改

number=["1","2","3"]
number[2]="8"  # 直接找到列表中的某个值，然后修改成其他数值
print(number)

['1', '2', '8']

删

• i .remove() 指定某个数据进行删除
• ii .pop() 当括号里没有任何数字时，不指定默认删除最后一个值
  • .pop(1) 当括号里有数字，指定数据进行删除
• iii del

number=["1","2","3","4"]
number.remove("3")
print(number)

['1', '2', '4']

number=["1","2","3","4"]
number.pop()
print(number)

['1', '2', '3']

number=["1","2","3","4"]
number.pop(0)
print(number)

['2', '3', '4']

number=["1","2","3","4"]
del number[1]   # del指定[x]某个位置上的值进行删除
print(number)

['1', '3', '4']

4. 列表排序

• .sort() 升序
• .reverse() 反转
• .sorted(变量，reverse=True) 降序
  • .sorted(变量，reverse=False) 升序

# 升序
number=["1","3","6","9","2"]
number.sort()
print(number)

['1', '2', '3', '6', '9']

# 反转
number=["1","3","6","9","2"]
number.reverse()
print(number)

['2', '9', '6', '3', '1']

# 降序
number=["1","3","6","9","2"]
number=sorted(number,reverse=True)
print(number)

['9', '6', '3', '2', '1']

# 升序
number=["1","3","6","9","2"]
sorted(number,reverse=False)
print(number)

['1', '3', '6', '9', '2']