journal of python(23) －－dive into python

4.9. Summary

4.9 小结

The apihelper.py program and its output should now make perfect sense.

整个程序apihelper.py以及它的输出现在都有意义了

 

def info(object, spacing=10, collapse=1):
    """Print methods and doc strings.

    Takes module, class, list, dictionary, or string."""
    methodList = [method for method in dir(object) if callable(getattr(object, method))]
    processFunc = collapse and (lambda s: " ".join(s.split())) or (lambda s: s)
    print "\n".join(["%s %s" %
                      (method.ljust(spacing),
                       processFunc(str(getattr(object, method).__doc__)))
                     for method in methodList])

if __name__ == "__main__":
    print info.__doc__
Here is the output of apihelper.py:

这是函数的输出

>>> from apihelper import info
>>> li = []
>>> info(li)
append     L.append(object) -- append object to end
count      L.count(value) -> integer -- return number of occurrences of value
extend     L.extend(list) -- extend list by appending list elements
index      L.index(value) -> integer -- return index of first occurrence of value
insert     L.insert(index, object) -- insert object before index
pop        L.pop([index]) -> item -- remove and return item at index (default last)
remove     L.remove(value) -- remove first occurrence of value
reverse    L.reverse() -- reverse *IN PLACE*
sort       L.sort([cmpfunc]) -- sort *IN PLACE*; if given, cmpfunc(x, y) -> -1, 0, 1

Before diving into the next chapter, make sure you're comfortable doing all of these things:

在继续阅读下章之前，请确保你自己已经掌握了下面的知识点：

• Defining and calling functions with optional and named arguments
• 定义以及调用一个带有可选参数的函数
• Using str to coerce any arbitrary value into a string representation
• 使用str强制转换任意属性值为一个字符串形式。
• Using getattr to get references to functions and other attributes dynamically
• 使用getattr来动态获得函数以及其它属性的引用
• Extending the list comprehension syntax to do list filtering
• 扩展list综合操作语法来实现链表过滤
• Recognizing the and-or trick and using it safely
• 识别and-or技巧同时能够安全的使用它。
• Defining lambda functions
• 定义lambda函数
• Assigning functions to variables and calling the function by referencing the variable. I can't emphasize this enough, because this mode of thought is vital to advancing your understanding of Python. You'll see more complex applications of this concept throughout this book.
• 将函数赋值给变量并通过引用变量来调用函数。对于这点，我强调的还不够多，这是因为这中思考方式对于提高你对python的理解至关重要。在本书你会看到更多的关于这种概念的复杂应用。