PHP

几乎每个标准函数都在全局作用域中 不一致的函数参数顺序 不一致的函数命名 不区分大小写的函数 脚本的行为可能会因php.ini文件的不同而有所不同 能够使用未定义的变量 在某些情况下，必须将结果赋值给变量，然后才能在函数中使用它

更主观地说:

动态类型

Python:

You usually have the entry point of the program at the end of the file. (Because if it calls any function defined in the module, it has to occur after those functions in the sources.) I hate it when you have to spend time looking for the entry point of a program, so I always have a simple main.py file with: def main(): ... if __name__ == '__main__': main() When an exception is raised, it can only be catched by the main thread. Or something like that. Destructors are quite useless, because when written in Python they may break garbage collection IIRC. I've never figured out how relative imports work in Python 2. I'd like to see more collections in the standard library. For example: linked lists, thread-safe collections, ...

我刚刚发现，在c#中创建泛型方法时，我不能使用Enum作为类型约束。

微软有一个足够好的解释，但仍然。我疯了

public static T MyFunc<T>(string arg) where T:Enum //wont work :(

C#

Reference types are nullable by default; in-language null keyword is untyped. Lack of discriminated unions Exceptions as default, non-exceptional error handling method - there's not much of an alternative. archaic switch statement syntax and limitations Needless distinction between constructors + static methods Static methods can't be part of an interface Lack of by-shape interface implementation rather than explicit interface implementation - leading to numerous language design hacks such as the linq query syntax, foreach, collection & object initializers -- none of which can be flexibly reused. For example, the object initializer syntax may be nice, but plays poorly with immutable objects. Cannot inherit "interface" of a class independently of implementation - leading to code duplications and overarchitected code that provides interfaces, abstract base classes, a few common implementations, and no way to pick and choose the bits of each to use. Also; leads to too many code that's tightly coupled to a particular implementation since it's common to explicitly refer to the implementation type rather than an interface. Cannot multiply inherit via composition since a classes "interface" is tightly coupled to it's implementation; effectively lack of mixins. The above limitations of interfaces lead to a proliferation of virtually identical interfaces that don't overlap naturally in any kind of type hierarchy. IComparable vs. IEquatable vs. IComparable<T> vs object.Equals vs. operator == etc. etc. By extension, making a custom type that satisfies all these things is a lot more work than necessary (in particular for collection classes). Obviously, the language designers realize this, hence the various workarounds for things like linq, foreach and collection initializers which work by-shape rather than by-interface. Redundant use of parentheses and braces rather than layout-is-structure. Return values can be ignored, limiting the effectiveness of type inference. Enums aren't a normal type and can't have methods. Also, enum values aren't typesafe and may be initialized to 0 despite not having a 0 value. Mixing metaphors by lumping flag and non-flag enums together. Lack of proper value type support. Value types can't be inherited, have different constructor semantics, and perform poorly due to CLR limitations. Also, confusing semantics regarding value types: some values are really values (and can't be modified), and others are really non-aliased, non-null references (variables). This gets particularly confusing with regards to the next issue: Semantic distinction between fields and properties, particularly in conjunction with lack of mutability modifier (ala C++'s const) Can't specialize generics Cannot provide default generic type parameters (e.g. factory generics) lack of typedef makes generics a pain to use (using is a limited but good-to-know substitute!) Can't genericize over things other than types (e.g. functions, plain values, or names). This means you can't do something like make a generic implementation of a dependancy property leading to, well, nasty implementations of things like dependancy properties and the overuse of code-snippets and poorly readable code as a result. Limited capability to specify generic type requirements e.g. generic sum method that takes both int, double and a bigint (without tricky and often slow hacks). An interface method implementation or virtual method override cannot return a more specific type or accept a more general type; i.e. limited co/contravariance support even in C# 4.

Python

No statements in lambdas. GRRRR foo( a for b in c if d ) feels wrong, it surprises me every time I get away with it. Shouldin't it be foo( (a for b in c if d) )? Can i have a dict comprehension? map and filter operators have special syntax in list comprehensions, how about something for reduce? or sort? Just by having a yield statement in it, a function is magically transformed into a generator, and its interface changes completely. Also, that generator cannot do any work before the first next(). at least, not without using a function that returns a generator.

JavaScript

No brief syntax for making modular code libraries. You have to call a function that returns a dictionary of public methods. And you have to edit that in (at least) two places every time you alter the interface of your module. Creating closures involves returning it from a function that returns a function from ('sup dog) yo' function. Clutter! for each ( foo ) syntax and behavior feels like an afterthought. Knowing when your code will actually run (and in what order) is more of a dark-art. The only way to get it right for sure is put everything (yes, that too) in one big file. and even then you still need to wait for a document.onload Am i missing something? is there no trivial way to get json serialized values without building them by hand? (yes jQuery can do this, sort of).

Python:

1) It's a scripting language and not a fully compiled one (I'd prefer to be able to compile binaries—I don't care about bytecode). This is very annoying if I have to use very many libraries (i.e. everyone who uses my program has to install all the libraries, and this basically means no normal people will be able to, or have the patience to, properly set it up—unless I do a ton of work that should be unnecessary). I know ways to make binaries, but they don't always work, and I'm guessing they bundle the interpreter in the binaries anyhow (and I don't want that). Now, if I could get a bytecode compiler that would include copies of all the files that I imported (and only those) to be placed in my program's folder, that might be a suitable compromise (then no one would have to download extra libraries and such). It would also be nice if the compiled python files could be compressed into a single file with one specified as the file to run the program before this is done.

2)有时看起来有点bug;有几次，应该工作的代码根本没有工作(没有程序员错误)，特别是与“from moduleX import *”和其他导入相关的问题有关的代码，以及一些与全局和局部变量有关的问题。

3)最大递归深度可以更高。至少有一次，我觉得我需要它去更高的地方。

4)没有switch语句(更不用说允许数字、字符串和范围的语句)

5)新版本的Python似乎取消了很多有用的字符串操作，而且似乎没有简单的文档说明如何在没有它们的情况下做同样的事情。

6)强制自动垃圾收集(我希望能够手动执行，尽管不一定强制执行)。

7)没有预先制作的定时器类没有使用GUI(好吧，可能有一个，但在我所做的所有搜索之后，它肯定不方便找到!我确实找到了一些东西，但当我尝试时，它根本不起作用。)所谓计时器，我指的是每隔x秒执行一个指定函数的排序，并能在需要时关闭它，等等。

8)社区里举例的人很少告诉我们他们导入了哪些模块，以及他们是如何导入的。

9)与Lua集成的支持并不多。

10)似乎没有办法向一个类的特定实例(而不是整个类)添加一个额外的函数，除非你动态地向该类添加一个对象变量，该对象具有所需的函数(但仍然，你必须为此创建另一个类)。