我刚刚发现了一个极好的、简洁的记忆方法:

动态/静态类型表达式;强/弱类型值。

Python是强类型的，因为它没有未检查的动态类型错误。换句话说，您不能违反它的类型系统。

定义

Type: set of values. It partially defines the intended usage (behaviour) of its values. It can be specified in extension with an enumeration or in intension with a predicate. Type system: system checking that values are used as intended, avoiding undefined behaviour partially. Undefined behaviour should be avoided because it can lead to late program crash or silent loss of data and production of incorrect results. Typed language: language with a type system. Type error: program error checkable by a type system. Expression: program text denoting a value. Static/dynamic type: compile-time/run-time type of an expression. The run-time type of an expression is the type of the value that it denotes. Static/dynamic type system: type system checking static/dynamic types. Statically/dynamically typed language: language with a static/dynamic type system. Static/dynamic type error: program error checkable by a static/dynamic type system. Weakly/strongly typed language: language with/without unchecked dynamic type errors. Statically typed, dynamically typed, or both imply strongly typed. Monomorphic/polymorphic expression: expression having a single dynamic type/multiple dynamic types. A monomorphic expression has single intended usage, and a polymorphic expression has multiple intended usage. Universal/ad-hoc polymorphic expression: real/virtual polymorphic expression. A real polymorphic expression denotes a single value that has multiple types, and a virtual polymorphic expression denotes multiple values that have single types. Parametric/inclusion polymorphic expression: universal polymorphic expression based on generic types/subtypes of a type (e.g. the C++ expression & denotes a single T* (T&) operator value where T is a generic type/the C++ expression std::exception denotes a single S class value where S is a generic subtype of std::exception). Overloading/coercion polymorphic expression: ad-hoc polymorphic expression based on expression/value conversion (e.g. the C++ expression + denotes int (int&, int&) and float (float&, float&) operator values/the C++ expression 3.5 denotes float and bool values).

参考

Cardelli (Luca)， Wegner (Peter)，“关于理解类型，数据抽象和多态性”，计算调查，第17卷，第4期，1985，第471-523页，DOI: https://doi.org/10.1145/6041.6042。

术语“强类型”没有明确的定义。

因此，这个词的使用取决于你和谁说话。

我不认为任何没有显式声明变量类型或没有静态类型的语言是强类型的。

强类型不只是排除转换(例如，“自动”将整数转换为字符串)。它排除了赋值(即改变变量的类型)。

如果以下代码编译(解释)，则该语言不是强类型的:

Foo = 1 Foo = "1"

在强类型语言中，程序员可以“依赖”类型。

例如，如果程序员看到声明，

UINT64 kZarkCount;

并且他或她知道20行之后，kZarkCount仍然是UINT64(只要它出现在同一个块中)——而不必检查中间的代码。

你混淆了“强类型”和“动态类型”。

我不能通过添加字符串'12'来改变1的类型，但我可以选择在变量中存储什么类型，并在程序运行时更改它。

与动态类型相对的是静态类型;变量类型的声明在程序的生命周期内不会改变。强类型的反面是弱类型;值的类型可以在程序的生命周期内更改。

我认为，这个简单的例子可以解释强类型和动态类型之间的区别:

>>> tup = ('1', 1, .1)
>>> for item in tup:
...     type(item)
...
<type 'str'>
<type 'int'>
<type 'float'>
>>>

java:

public static void main(String[] args) {
        int i = 1;
        i = "1"; //will be error
        i = '0.1'; // will be error
    }

class testme(object):
    ''' A test object '''
    def __init__(self):
        self.y = 0

def f(aTestMe1, aTestMe2):
    return aTestMe1.y + aTestMe2.y




c = testme            #get a variable to the class
c.x = 10              #add an attribute x inital value 10
c.y = 4               #change the default attribute value of y to 4

t = testme()          # declare t to be an instance object of testme
r = testme()          # declare r to be an instance object of testme

t.y = 6               # set t.y to a number
r.y = 7               # set r.y to a number

print(f(r,t))         # call function designed to operate on testme objects

r.y = "I am r.y"      # redefine r.y to be a string

print(f(r,t))         #POW!!!!  not good....

在一个大型系统中，上述情况会在很长一段时间内造成代码不可维护的噩梦。随便你怎么称呼它，但“动态”改变变量类型的能力只是一个坏主意……