Python常用方法和技巧汇总

def reverse(text) : str = '' index = len(text) - 1 while index >= 0 : str += text[index] index -= 1 return str

def reverse_1(text) : return text[::-1]

def reverse_2(text) : temp = list(text) temp.reverse() return ''.join(temp)

def reverse_3(text) : return reduce(lambda x, y : y + x, text) print reverse_3("Hello")

dict={"a":"apple","b":"banana","o":"orange"} print "##########dict######################" for i in dict: print "dict[%s]=" % i,dict[i] print "###########items#####################" for (k,v) in dict.items(): print "dict[%s]=" % k,v print "###########iteritems#################" for k,v in dict.iteritems(): print "dict[%s]=" % k,v print "###########iterkeys,itervalues#######" for k,v in zip(dict.iterkeys(),dict.itervalues()): print "dict[%s]=" % k,v

for key in lst : print key for i in range(len(lst)) : print lst[i] for index, key in enumerate(lst) : print key //index是list的索引

dic = {'a':31, 'bc':5, 'c':3, 'asd':4, 'aa':74, 'd':0} dict= sorted(dic.iteritems(), key=lambda d:d[1], reverse = True) print dict //输出的结果： [('aa', 74), ('a', 31), ('bc', 5), ('asd', 4), ('c', 3), ('d', 0)]

dic = {'a':31, 'bc':5, 'c':3, 'asd':4, 'aa':74, 'd':0} dict= sorted(dic.iteritems(), key=lambda d:d[0]) # d[0]表示字典的键 print dict #sorted中第三个可选参数为reverse, True表示从大到小排序 #默认reverse = False

class A(object) : def init(self) : print "testA class B(A) : def init(self) : A.init(self)

super().fuleifunction()

func2(a=1, b=2, c=3) #默认参数 func3(*args) #接受任意数量的参数, 以tuple的方式传入 func4(**kargs) #把参数以键值对字典的形式传入

def calcSum(*args): sum = 0 for i in args: sum += i print sum #调用： calcSum(1,2,3) calcSum(123,456) calcSum() #输出： 6 579 0 ################################# def printAll(**kargs): for k in kargs: print k, ':', kargs[k] printAll(a=1, b=2, c=3) printAll(x=4, y=5) #输出： a : 1 c : 3 b : 2 y : 5 x : 4

def fn(x): return lambda y: x + y #调用 a = fn(2) print a(3) #输出 5