This is a bit like javascriptvar
in js

for(var i = 0; i < 100; i++){
    //内容
}
console.log(i);//i = 100

Because the scope of variables defined in js var定义的变量的作用域是整个函数，所以ES6语法中增加了一个let，let定义的变量就是块级作用域
如果是for(let i = 0; i < 100; i++)，后面再log i的话就是undefined is the entire function, so a let is added to the ES6 syntax, and the variables defined by let are block-level scope

for(int i = 0; i < 100; i ++){
    //i在块级作用域范围内
}

You change it to this and print out the locals() function

def find(sequence, target):
    for index, value in enumerate(sequence):
        if value == target:
            break
    else:
        return -1
    print(locals())
    return index
    

will find the output

{'index': 1, 'target': 1, 'value': 1, 'sequence': [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]}

You can see from the output that index, value, target, and sequence are in the same namespace. Because they are both in the same function. So you can access the index.

Scope of python

1. Search at the innermost level, usually in a function, locals()

2. Search within the module, i.e. globals()

3. Search outside the module, that is, search in __builtin__

Python has no block scope

The smallest range is function

Simply put, in python only modules, classes, and functions will create new scopes, so the variables defined in the for loop can also be accessed outside the loop, as long as they are in the same scope