[Python for Data Analysis] Python Basic--Function_python fucntion-basic命令是干什么-优快云博客

本文链接：https://blog.youkuaiyun.com/jaskson/article/details/50649500

本文深入探讨了Python函数的基本概念、参数类型、作用域、闭包、lambda函数及高级特性，包括多重返回值、使用*args和**kwargs、部分参数应用等。同时涉及生成器和迭代器模块的应用，以及文件与操作系统交互的基础知识。

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argument

可以是scalar type, 也可以是list等data structure,可以是function
object都可以

Positional arguments and keywords argument

In [3]:

def my_function(x,y,z = 1.5):
    if z>1:
        return z*(x+y)
    else:
        return z/(x+y)
my_function(5,6,z = 0.7),my_function(3.14,7,3.5)
Out[3]:
(0.06363636363636363, 35.49)

Namespace, Scope, Local Functions

没有太多意思, 注意变量的存在范围, 以及在函数内部也可以定义函数
In [4]:

returning Multiple Values

def f():
    a = 5
    b = 6
    c = 7
    return a,b,c #returning a tuple
a,b,c = f()
print a,b,c
5 6 7

function are objects

we can use get a collection of fuctions using their names, they can be used as arguments
b = foo is an assignment

In [6]:

def addOne(x):
    return x+1
def multiTwo(x):
    return x*2
def minusTwo(x):
    return x-2
def devTwo(x):
    return x/2
def clear(x,ops):
    for function in ops:
        x = function(x)
    return x
clear(5,[addOne,multiTwo,minusTwo,devTwo])
Out[6]:
5

lambda functions

关键词,lambda

In [9]:

#if we want to sort string using the number of unique characters
strings = ['abc','aaab','aaaaa']
strings.sort(key = lambda x: len(set(list(x))))
strings
Out[9]:
['aaaaa', 'aaab', 'abc']

Closures: Functions that Return Functions

暂时用不到

Extended Call Synatx with *args, **kw args

暂时用不到

Currying: Partial Argument Application

可以简化给定的函数

#在pandas处理时可能用到
#ma60 = lambda x:pandas.rolling_mean(x,60)
#data.apply(m60)

Generators

Itertools module

Files and Operating system

通常情况下, 用pandas.read_csv() to read data files into Python Data Structure