数组部分选择不能给你所要求的。

[1]给出一个元素 A[1:2]给出一个元素，而不是[A [1]， A [2]] A[1:3]给出2个元素

我讨厌这样，但可能是因为我大部分时间都在Verilog上工作。

c#中缺少预处理器。

我知道他们把它放在一边是因为有些人会滥用它，但我认为他们把孩子和洗澡水一起倒掉了。代码生成被认为是一件好事，在c++中，预处理程序是我的第一个代码生成器。

Java -不支持语言级别的组合

关于c#:

I hate that there is no keyword to specify which exceptions are thrown from a method like in java. Its a much better way to document exceptions than using an XML comment. I would also want a much better syntax for generic constraints like oring and anding of constraints. Why a method can't return more than one value? Lack of support for aspect oriented programming in the language. Why can't you annotate each one of the property accessors with an attribute? Lack of builtin regexp support like in perl.

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

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