python 代码实例

Python是一种高级编程语言，以其简洁的语法和强大的功能著称。以下是一个简单的Python代码示例，它演示了如何使用Python进行基本的文件读写操作：

# 打开一个文件用于写入，如果文件不存在则创建它
with open('test.txt', 'w') as file:
    file.write('这是一个测试文件。\n')
    file.write('这是第二行。\n')

# 打开文件用于读取
with open('test.txt', 'r') as file:
    content = file.read()
    print(content)

# 使用readlines()方法读取文件的每一行，然后打印每行内容
with open('test.txt', 'r') as file:
    lines = file.readlines()
    for line in lines:
        print(line.strip())  # strip()方法用于删除字符串头尾指定的字符（默认为空格或换行符）或字符序列

这个简单的例子展示了文件的打开、内容的写入、读取以及逐行读取，并且使用了`with`语句来确保文件在操作完成后能够正确关闭。

相关问题

python代码实例

回答: 以下是几个Python代码实例:
1. 异常处理:

a, b = 1, 0
try:
    print(a/b)
except ZeroDivisionError:
    print("Can not divide by zero")
finally:
    print("Executing finally block")

<span class="em">1</span><span class="em">2</span><span class="em">3</span>
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神经网络python代码实例

下面是一个神经网络的Python代码实例：

import numpy as np

def sigmoid(x):
    return 1 / (1 + np.exp(-x))

class Neuron:
    def __init__(self, weights, bias):
        self.weights = weights
        self.bias = bias

    def feedforward(self, inputs):
        total = np.dot(self.weights, inputs) + self.bias
        return sigmoid(total)

class OurNeuralNetwork:
    def __init__(self):
        weights = np.array([0, 1])
        bias = 0
        self.h1 = Neuron(weights, bias)
        self.h2 = Neuron(weights, bias)
        self.o1 = Neuron(weights, bias)

    def feedforward(self, x):
        out_h1 = self.h1.feedforward(x)
        out_h2 = self.h2.feedforward(x)
        out_o1 = self.o1.feedforward(np.array([out_h1, out_h2]))
        return out_o1

network = OurNeuralNetwork()
x = np.array([2, 3])
print(network.feedforward(x)) # 输出0.7216325609518421

希望这个例子能够帮助你理解神经网络的实现过程。