Python 替换行符导致文字丢失：
从网页爬取一段文字：
Consider the half-eigenvalue problem [公式] a.e.
[公式], where [公式], [公式], [公式] for [公式], and [公式] and [公式] are indefinite integrable weights in the Lebesgue
space [公式]. We characterize the spectra structure under periodic, antiperiodic, Dirichlet, and Neumann boundary conditions, respectively. Furthermore, all these half-eigenvalues are continuous in [公式], where [公式] denotes the weak topology in [公式] space. The Dirichlet and the Neumann half-eigenvalues are continuously Fréchet differentiable in [公式], where [公式] is the [公式] norm of [公式].
我使用 python 字符串 replace()方法将 \n 替换为空，出现了这样的情况：
space [公式]. We characterize the spectra structure under periodic, antiperiodic, Dirichlet, and Neumann boundary conditions, respectively. Furthermore, all these half-eigenvalues are continuous in [公式], where [公式] denotes the weak topology in [公式] space. The Dirichlet and the Neumann half-eigenvalues are continuously Fréchet differentiable in [公式], where [公式] is the [公式] norm of [公式].
对，没错，上面两行数据莫名消失了！！
我仅仅是这么做了而已：
content.replace('\n', '')
到底出了什么问题呢？
答案超乎我的意料——
我们加一个方括号，这样就能查看编码了，于是：
print([content])
它的打印结果是：
['Consider the half-eigenvalue problem [公式] a.e. \r\n[公式], where [公式], [公式], [公式] for [公式], and [公式] and [公式] are indefinite integrable weights in the Lebesgue\r\nspace [公式]. We characterize the spectra structure under periodic, antiperiodic, Dirichlet, and Neumann boundary conditions, respectively. Furthermore, all these half-eigenvalues are continuous in [公式], where [公式] denotes the weak topology in [公式] space. The Dirichlet and the Neumann half-eigenvalues are continuously Fréchet differentiable in [公式], where [公式] is the [公式] norm of [公式].']
居然含有\r（极有可能是 windows 操作系统特有的问题）我们如何还原呢？当然是把\r 也替换掉
print(content.replace('\r','').replace('\n',''))
这样就没有问题了，至于为什么不直接写为 replace(‘\r\n’,’’)，你猜有没有可能有些字符串中没有\r 但有些有，所以分开写不会报错
