python_索引_切片

 

一.   索引

1.索引值以 0 为开始值，-1 为从末尾的开始位置。

取值格式var[index] 

字符串索引

name="hello_shenzhen"

print(name[0])

print(name[1])

print(name[-1])

print(name[-2])

列表索引

phone=['huawei','sanxing','apple','xiaomi','zhongxin']
print(phone[0])
print(phone[1])
print(phone[-1])
print(phone[-2])

3.多维数组，索引取值

"""多维数组，索引取值"""

 

name=("zhangsan","lisi",("liudehua","telangpu","tainmao"),"wangwu","zhaoliu","wangba")
print(name[2][-1])

 

 

phone=['huawei','sanxing','apple','xiaomi','zhongxin',['huojiya','xiaolingtong']]
print(phone[0])
print(phone[1])
print(phone[-1])
print(phone[-2])
print(phone[5][-1])

二.切片　　var[start_index:end_index]

注意：切出的值不包含end_index的值

1.      正切

name="shenzhenwuya"
print(name[2:6])#取值从3—6

结果：enzh

print(name[3:7])

结果：nzhe

print(name[0:11])

结果：shenzhenwuy

print(name[0:])

结果：shenzhenwuya

print(name[:])

结果：shenzhenwuya

 

 

2.反切

name="shenzhenwuya"

print(name[:-1])

结果：shenzhenwuy

print(name[:-2])

结果：shenzhenwu

print(name[4:-4])

结果：zhen

 

1. 跳级切

name="shenzhenwuya"

print(name[1:8:])

结果：henzhen

print(name[1:8:1])

结果：henzhen

print(name[1:8:2])

结果：hnhn

print(name[1:8:3])

结果：hzn

print(name[::2])

结果：sezewy

 

4.反跳级切

name="shenzhenwuya"

print(name[-12:-4:])

结果：shenzhen

print(name[-12:-4:1])

结果：shenzhen

print(name[-12:-4:2])

结果：seze

print(name[-12:-4:3])

结果：sne

print(name[::3])

结果：sneu

注意：整型int和字典dict和集合set不支持索引取值