Python

那些我不理解的…

math.ceil() and math.floor() return floats, not integers (probably to avoid an integer overflow in the underlying C function - but why not cast to a Python long?) len() is a function not a method reload() is very limited, does not reload a module 9 times out of 10, only reloads an imported label if it is a module - i.e. cannot do from bar import foo; reload(foo) if foo is not itself a module Mutable default arguments have a single reference (why not a new instance each function call?!) All these underscored variables - if they are so private, how come we see inbuilt ones so much in code? Get a namespace! Strings are not mutable - maybe there is a good reason for this but I have come across many situations where I would like to tweak one particular character ...

那些基于实现有意义但令人讨厌的……

array.sort()不返回数组(我认为它发生在原地) 列表/生成器推导式不定义新的作用域(只是for循环的语法糖，对吗?)

以及几个在Python 3中修复的

默认为整数除法 Global只能引用顶级名称空间

c#:

1)静态方法必须是类的成员

2)静态扩展方法只能添加到静态类中

3)接口函数的实现不会被标记为“override”之类的东西来显示它们来自基类或接口(这使得你很难确保你正在重写你所期望的方法(具有正确的签名))。

我只有3个。我想那很好。

JavaScript:

The Object prototype can be modified. Every single object in your program gets new properties, and something probably breaks. All objects are hash maps, but it's difficult to safely use them as such. In particular, if one of your keys happens to be __proto__, you're in trouble. No object closure at function reference time. In fact, no object closure at all -- instead, this is set whenever a function is called with object notation or the new operator. Results in much confusion, particularly when creating event callbacks, because this isn't set to what the programmer expects. Corollary: calling a function without object notation or the new operator results in this being set equal to the global object, resulting in much breakage. Addition operator overloaded to also perform string concatenation, despite the two operations being fundamentally different. Results in pain when a value you expect to be a number is in fact a string. == and != operators perform type coercion. Comparisons between different types involve a list of rules that no mortal can remember in full. This is mitigated by the existence of === and !== operators. Both null and undefined exist, with subtly different, yet redundant meanings. Why? Weird syntax for setting up prototype chains. parseInt(s) expects a C-style number, so treats values with leading zeroes as octal, etc. You can at least parseInt(s, 10) but the default behaviour is confusing. No block scope. Can declare the same variable more than once. Can use a variable without declaring it, in which case it's global and probably breaks your program. with { }. Really difficult to document with JavaDoc like tools.

Ruby

无类型推断 方法/函数不是一级对象 变量的范围不是词法的，尽管块变量的范围是词法的 Def内部的Def super和super()的区别

JavaScript

ECMAScript 5规范:

7.6.1.2未来保留词: 类，enum, extends, super, const, export， 进口 严格模式:实现、let、private、public、interface、package、protected、static、yield 11.9.4严格等于操作符(===)对比11.9.1 TheEqualsOperator(==) 11.9.6严格相等比较算法(NaN === NaN is false) 8.5数字类型-没有实整数，所有都是浮点数。 4.2.1对象——原型继承

好吧，我有点喜欢最后一个，但它有7种让人困惑的地方

很多人认为Java很慢，但我同意一定程度的使用。

Java是戏剧性的。他们为你想做的一件事提供了很多课程。但是你知道灵活性属性XD。

Java一开始很难，但总是很有趣。

当你写一个简单的代码打印“Hello,World!”请不要使用java !XD我相信我是有道理的。

Java是一种混合，所以不要说它是纯粹的面向对象语言。

还有很多，但我只局限于5个XD。谢谢!