问题描述
基本上,我希望能够知道我何时在循环迭代中的第 N 个项目上.有什么想法吗?
Basically I would like to be able to tell when I'm on the Nth item in a loop iteration. Any thoughts?
d = {1:2, 3:4, 5:6, 7:8, 9:0} for x in d: if last item: # <-- this line is psuedo code print "last item :", x else: print x
推荐答案
使用 枚举:
#!/usr/bin/env python d = {1:2, 3:4, 5:6, 7:8, 9:0} # If you want an ordered dictionary (and have python 2.7/3.2), # uncomment the next lines: # from collections import OrderedDict # d = OrderedDict(sorted(d.items(), key=lambda t: t[0])) last = len(d) - 1 for i, x in enumerate(d): if i == last: print i, x, 'last' else: print i, x # Output: # 0 1 # 1 3 # 2 9 # 3 5 # 4 7 last