内建方法
map函数
map函数会根据提供的函数对制定序列做映射
#函数需要一个参数
map(lambda x:x*x,[1,2,3])
#结果为:[1,4,9]
1 def f1(x,y): 2 return(x,y) 3 l1 = [0,1,2,3,4,5,6] 4 l2 = ["Sun","M","T","W","T","F","S"] 5 l3 = map(f1,l1,l2) 6 print(list(l3)) 7 #结果是:[(0,"Sun"),(1,"M"),(2,"T"),(3,"w"),(4,"T"),(5,"F"),(6,"S")]
filter函数
filter函数会对指定序列执行过滤操作
filter(lambda x:x%2,[1,2,3,4])#x%2是对x取余
#结果:[1,3]
reduce函数
reduce函数会对参数序列中元素进行累积
reduce(lambda x,y:x+y,[1,2,3,4])
#结果:10
reduce(lambda x,y:x+y,[“aa”,“bb”,“cc”],"dd")
"ddaabbcc"
sorted函数
进行排序
sorted ([1,4,2,6,3,5])
结果:[1,2,3,4,5,6]
sorted([1,4,2,6,3,5],reverse=1)
结果:[6,5,4,3,2,1]