我可以使用' print‘打印出python列表，但不能使用return

Question

我无法使用return函数打印最终值。我的代码：

    def filter_wave(wave,n):
        new_wave = [i for i in wave]
        for k in range(n):
            for i in range(len(wave)):
                curr_wave = new_wave.copy()
                if(i==0):
                    new_wave[i] = int(curr_wave[i]*0.6+curr_wave[i+1]*0.2)
                elif(i>0 and i<len(wave)-1):
                    new_wave[i] = int(curr_wave[i-1]*0.2+curr_wave[i]*0.6+curr_wave[i+1]*0.2)
                else:
                    new_wave[i] = int(curr_wave[i-1]*0.2+curr_wave[i]*0.6)
        print(new_wave)

在迭代n次之后，它应该会返回最后一个波。print()可以工作，但如果我尝试return，它不能工作。错误是什么？

Image of successful print()

Image of unsuccessful return

Answer 1

如果我正确理解了您的问题，如果您通过运行以下代码行来调用函数

filter_wave(original_wave_sample, 200)

您希望输出等于打印的变量new_wave

当您在正文中使用print()而不使用return语句打印变量时，变量将打印到屏幕上。如果使用return( new_wave )，则必须指定一个变量来存储返回的变量new_wave：

使用函数中的返回值(New_wave)：

result = filter_wave(original_wave_sample, 200)
print(result)

完整示例：

 def filter_wave(wave,n):
    new_wave = [i for i in wave]
    for k in range(n):
        for i in range(len(wave)):
            curr_wave = new_wave.copy()
            if(i==0):
                new_wave[i] = int(curr_wave[i]*0.6+curr_wave[i+1]*0.2)
            elif(i>0 and i<len(wave)-1):
                new_wave[i] = int(curr_wave[i-1]*0.2+curr_wave[i]*0.6+curr_wave[i+1]*0.2)
            else:
                new_wave[i] = int(curr_wave[i-1]*0.2+curr_wave[i]*0.6)
    return(new_wave)

result = filter_wave(original_wave_sample, 200)
print(result)