访问 tuple
可以使用 index 的方式对 tuple 进行访问,比如下面访问 tuple 中的第二个元素。
thistuple &＃61; ("apple", "banana", "cherry")
print(thistuple[1])
PS E:\dream\markdown\python> & "C:/Program Files (x86)/Python/python.exe" e:/dream/markdown/python/app/app.py
banana
负数 index
负数索引意味着从后往前计算&＃xff0c;比如说&＃xff1a;-1 表示最后一项&＃xff0c; -2 表示倒数第二项&＃xff0c;代码如下&＃xff1a;
thistuple &＃61; ("apple", "banana", "cherry")
print(thistuple[-1])
范围 index
可以指定一个范围的 start 和 end 来指定一个 tuple 的 子区间&＃xff0c;返回值就是一个新生成的 tuple&＃xff0c;如下代码所示&＃xff1a;
thistuple &＃61; ("apple", "banana", "cherry", "orange", "kiwi", "melon", "mango")
print(thistuple[2:5])
PS E:\dream\markdown\python> & "C:/Program Files (x86)/Python/python.exe" e:/dream/markdown/python/app/app.py
(&＃39;cherry&＃39;, &＃39;orange&＃39;, &＃39;kiwi&＃39;)
负数的范围索引
如果你想从 tuple 的尾部往前进行切割&＃xff0c;可以指定负数的 index&＃xff0c;如下代码所示&＃xff1a;
thistuple &＃61; ("apple", "banana", "cherry", "orange", "kiwi", "melon", "mango")
print(thistuple[-4:-1])
PS E:\dream\markdown\python> & "C:/Program Files (x86)/Python/python.exe" e:/dream/markdown/python/app/app.py
(&＃39;orange&＃39;, &＃39;kiwi&＃39;, &＃39;melon&＃39;)
检查 item 是否存在
检查 tuple 中的某一项是否存在&＃xff0c;可以使用 in 关键词。
thistuple &＃61; ("apple", "banana", "cherry")
if "apple" in thistuple:
print("Yes, &＃39;apple&＃39; is in the fruits tuple")
更新 tuple
tuple 是不可修改的&＃xff0c;意味着一旦 tuple 创建好之后&＃xff0c;你不能对其进行新增&＃xff0c;删除&＃xff0c;修改&＃xff0c;但也有一些变通方法。
修改 tuple 值
变通方法就是&＃xff0c;可以先将 tuple 转成 list&＃xff0c;然后在 list 上进行修改&＃xff0c;最后再将 list 转成 tuple 即可&＃xff0c;如下代码所示&＃xff1a;
x &＃61; ("apple", "banana", "cherry")
y &＃61; list(x)
y[1] &＃61; "kiwi"
x &＃61; tuple(y)
print(x)
PS E:\dream\markdown\python> & "C:/Program Files (x86)/Python/python.exe" e:/dream/markdown/python/app/app.py
(&＃39;apple&＃39;, &＃39;kiwi&＃39;, &＃39;cherry&＃39;)
tuple中新增 / 删除
同样的道理&＃xff0c;还是使用 list 作为中间转换&＃xff0c;实现 tuple 的 add / remove 操作&＃xff0c;代码如下&＃xff1a;
thistuple &＃61; ("apple", "banana", "cherry")
y &＃61; list(thistuple)
y.append("orange")
thistuple &＃61; tuple(y)
print(thistuple)
PS E:\dream\markdown\python> & "C:/Program Files (x86)/Python/python.exe" e:/dream/markdown/python/app/app.py
(&＃39;apple&＃39;, &＃39;banana&＃39;, &＃39;cherry&＃39;, &＃39;orange&＃39;)
thistuple &＃61; ("apple", "banana", "cherry")
y &＃61; list(thistuple)
y.remove("apple")
thistuple &＃61; tuple(y)
print(thistuple)
PS E:\dream\markdown\python> & "C:/Program Files (x86)/Python/python.exe" e:/dream/markdown/python/app/app.py
(&＃39;banana&＃39;, &＃39;cherry&＃39;)
肢解 tuple
现在有了一个 tuple&＃xff0c;那如何将 tuple 中的值肢解到几个变量中呢&＃xff1f;这就需要使用 unpacking 操作&＃xff0c;代码如下&＃xff1a;
fruits &＃61; ("apple", "banana", "cherry")
(green, yellow, red) &＃61; fruits
print(green)
print(yellow)
print(red)
PS E:\dream\markdown\python> & "C:/Program Files (x86)/Python/python.exe" e:/dream/markdown/python/app/app.py
apple
banana
cherry
tuple 中的 * 操作
如果需要肢解的 tuple 个数大于左边的变量个数&＃xff0c;那么可以将一个变量声明成 * &＃xff0c;表示将 多余的 tuple 元素作为一个集合赋给 *号变量&＃xff0c;如果不明白的话&＃xff0c;参考下面代码&＃xff1a;
fruits &＃61; ("apple", "banana", "cherry", "strawberry", "raspberry")
(green, yellow, *red) &＃61; fruits
print(green)
print(yellow)
print(red)
PS E:\dream\markdown\python> & "C:/Program Files (x86)/Python/python.exe" e:/dream/markdown/python/app/app.py
apple
banana
[&＃39;cherry&＃39;, &＃39;strawberry&＃39;, &＃39;raspberry&＃39;]
同样这个 *号变量 也可以指定任意位置&＃xff0c;如下代码所示&＃xff1a;
fruits &＃61; ("apple", "mango", "papaya", "pineapple", "cherry")
(green, *tropic, red) &＃61; fruits
print(green)
print(tropic)
print(red)
PS E:\dream\markdown\python> & "C:/Program Files (x86)/Python/python.exe" e:/dream/markdown/python/app/app.py
apple
[&＃39;mango&＃39;, &＃39;papaya&＃39;, &＃39;pineapple&＃39;]
cherry
tuple 遍历
遍历 tuple 通常有两种做法。
使用 for 循环
thistuple &＃61; ("apple", "banana", "cherry")
for x in thistuple:
print(x)
使用 range() &＃43; len()
除了简单粗暴的 for 循环&＃xff0c;还可以利用下标实现 for 操作&＃xff0c;代码如下&＃xff1a;
thistuple &＃61; ("apple", "banana", "cherry")
for i in range(len(thistuple)):
print(thistuple[i])
使用 while 循环
也可以通过 len() 获取tuple 的长度&＃xff0c;然后使用 while 循环&＃xff0c;不过这里记得在循环的过程中&＃xff0c;要记得将下标自增&＃xff0c;如下代码所示&＃xff1a;
thistuple &＃61; ("apple", "banana", "cherry")
i &＃61; 0
while i
print(thistuple[i])
i &＃61; i &＃43; 1
PS E:\dream\markdown\python> & "C:/Program Files (x86)/Python/python.exe" e:/dream/markdown/python/app/app.py
apple
banana
cherry
tuple 合并
合并多个 tuple 也是非常简单的&＃xff0c;通常有二种做法。
操作
可以直接在两个 tuple 中使用 &＃43; 操作&＃xff0c;如下代码所示&＃xff1a;
tuple1 &＃61; ("a", "b" , "c")
tuple2 &＃61; (1, 2, 3)
tuple3 &＃61; tuple1 &＃43; tuple2
print(tuple3)
PS E:\dream\markdown\python> & "C:/Program Files (x86)/Python/python.exe" e:/dream/markdown/python/app/app.py
(&＃39;a&＃39;, &＃39;b&＃39;, &＃39;c&＃39;, 1, 2, 3)
x 操作
如果想让 tuple 中内容重复出现几次&＃xff0c;这个几次可以使用 x num 的操作&＃xff0c;这里的 num 就是几次的意思&＃xff0c;如下代码所示&＃xff1a;
fruits &＃61; ("apple", "banana", "cherry")
mytuple &＃61; fruits * 2
print(mytuple)
PS E:\dream\markdown\python> & "C:/Program Files (x86)/Python/python.exe" e:/dream/markdown/python/app/app.py
(&＃39;apple&＃39;, &＃39;banana&＃39;, &＃39;cherry&＃39;, &＃39;apple&＃39;, &＃39;banana&＃39;, &＃39;cherry&＃39;)
其他的 tuple 方法
除了上面介绍的几个&＃xff0c;tuple 还有如下几个内建方法。
译文链接&＃xff1a;https://www.w3schools.com/python/python_tuples_access.asp
更多高质量干货&＃xff1a;参见我的 GitHub: python
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