Question

我是python的新手我找到了这个问题的一些答案，但没有什么能真正帮助我。

这里是我遇到问题的代码部分：

batch_index=0 # initializing a globale variable, I've tried with global batch_index too 
..................................

def next_Training_Batch():
    if  batch_index < len(train_data):
        batch_index = batch_index + 1
        return train_data[batch_index-1], train_labels[batch_index-1]
    else :
        shuffle_data()
        batch_index = 0
        return train_data[batch_index], train_labels[batch_index]

当我调用该函数时，我得到以下内容：

UnboundLocalError: local variable 'batch_index' referenced before assignment

我不想在函数中使用参数（如类似问题所示）并且说实话，我使用＆＃34; global＆＃34;变量没有任何错误，我不明白为什么我不允许在if语句中对它进行评估？谢谢你的暗示！

Answer 1

将global batch_index添加到函数的开头，它将知道您指的是全局变量而不是本地变量。

batch_index=0 # initializing a globale variable, I've tried with global batch_index too 
...

def next_Training_Batch():
    global batch_index
    if batch_index < len(train_data):
        batch_index = batch_index + 1
        return train_data[batch_index - 1], train_labels[batch_index - 1]
    else:
        shuffle_data()
        batch_index = 0
        return tain_data[batch_index], train_labels[batch_index]

Answer 2

使用创建变量副本的全局关键字

def next_Training_Batch():
    global batch_index
    if  batch_index < len(train_data):
        batch_index = batch_index + 1
        return train_data[batch_index-1], train_labels[batch_index-1]
    else :
        shuffle_data()
        batch_index = 0
        return tain_data[batch_index], train_labels[batch_index]

但仍未定义train_data

Answer 3

在函数中使用全局说全局batch_index

batch_index = 0＃初始化全局变量，我也试过全局batch_index

def next_Training_Batch():
    global batch_index
    if  batch_index < len(train_data):
        batch_index = batch_index + 1
        return train_data[batch_index-1], train_labels[batch_index-1]
    else :
        shuffle_data()
        batch_index = 0
        return tain_data[batch_index], train_labels[batch_index]

赋值前引用的局部变量

3 个答案: