if not a: print "List is empty"
这里是因为空列表会返回一个False
获取列表的索引和值ints = [8, 23, 45, 12, 78]for idx, val in enumerate(ints): print idx, val0 81 232 453 124 78合并列表中的子列表1 method
l=[[1,2,3],[4,5,6], [7], [8,9]] print([item for sublist in l for item in sublist]) [1, 2, 3, 4, 5, 6, 7, 8, 9]2 method
l=[[1,2,3],[4,5,6], [7], [8,9]] print(sum(l, [])) [1, 2, 3, 4, 5, 6, 7, 8, 9]3 method
from functools import reduce l=[[1,2,3],[4,5,6], [7], [8,9]] print(reduce(lambda x,y: x+y,l)) [1, 2, 3, 4, 5, 6, 7, 8, 9]
第一种方法是速度最快的方法
列表中字典的值排序list_to_be_sorted = [{'name':'Homer', 'age':39}, {'name':'Bart', 'age':10}]from operator import itemgetter
newlist = sorted(list_to_be_sorted, key=itemgetter('name'))
print(newlist)把列表分割成同样大小的块tuple(l[i:i+n] for i in xrange(0, len(l), n))def chunks(l, n): """ Yield successive n-sized chunks from l. """ for i in xrange(0, len(l), n): yield l[i:i+n]合并两个列表
mergedlist = listone + listtwo列表中随机取一个元素
foo = ['a', 'b', 'c', 'd', 'e'] print(random.choice(foo))按照步长遍历列表
a[start:end:step] # 按照step步长直到end-1结束,并不是从start一个个遍历到endPython中的appen和extend
x = [1, 2, 3] x.append([4, 5])print (x) 输出:[1, 2, 3, [4, 5]]
x = [1, 2, 3] x.extend([4, 5])print (x) 输出:[1, 2, 3, 4, 5]
作者：张晓天a
链接：https://www.jianshu.com/p/d2cb34126d7b
