[英]sorted() with lambda function
I have strings that look like "co1/co2", "co3/co4" ... "co11/co12" 我的字符串看起来像“co1 / co2”,“co3 / co4”......“co11 / co12”
describing it as a regex: 将其描述为正则表达式:
^(?P<prefix>\w\w)(?P<month>\d+)/(?P<prefix2>\w\w)(?P<month2>\d+)$
I want to sort a collection of these strings based on the equivalent of the "month" group of the regex. 我想根据正则表达式的“月”组的等价物对这些字符串的集合进行排序。 (the first number in the string (eg. the "1" in 'co1/co2' or the "12" in 'co12/co13')
(字符串中的第一个数字(例如,'co1 / co2'中的“1”或'co12 / co13中的“12”)
I'm unable to figure out a lambda function I can use in sorted() that will do this for me, though. 我无法弄清楚我可以在sorted()中使用的lambda函数,但是我会这样做。
wrong_order = [u'co1/co2', u'co10/co11', u'co11/co12', u'co12/co13', u'co2/co3',
u'co3/co4', u'co4/co5', u'co5/co6', u'co6/co7', u'co7/co8', u'co8/co9',
u'co9/co10']
correct_order = [u'co1/co2', u'co2/co3', u'co3/co4', u'co4/co5', u'co5/co6', \
u'co6/co7', u'co7/co8', u'co8/co9', u'co9/co10', u'co10/co11', u'co11/co12', u'co12/co13']
#this lambda function doesn't work
output = sorted(wrong_order, key=lambda x: (x[2:]))
Without a regex: 没有正则表达式:
lambda x: int(x.partition('/')[0][2:])
This takes the part of the string before the /
, then everything but the starting co
, then converts that to an integer. 这将在
/
之前获取字符串的一部分,然后除了起始co
所有内容,然后将其转换为整数。
I used str.partition()
as it is faster than str.split()
for the split only once case. 我使用
str.partition()
因为它比str.split()
更快, 只有一次拆分 。
Demo: 演示:
>>> wrong_order = [u'co1/co2', u'co10/co11', u'co11/co12', u'co12/co13', u'co2/co3',
... u'co3/co4', u'co4/co5', u'co5/co6', u'co6/co7', u'co7/co8', u'co8/co9',
... u'co9/co10']
>>> sorted(wrong_order, key=lambda x: int(x.partition('/')[0][2:]))
[u'co1/co2', u'co2/co3', u'co3/co4', u'co4/co5', u'co5/co6', u'co6/co7', u'co7/co8', u'co8/co9', u'co9/co10', u'co10/co11', u'co11/co12', u'co12/co13']
try this: 尝试这个:
>>> sorted(wrong_order, key = lambda x:int(x.split("/")[0][2:]))
[u'co1/co2', u'co2/co3', u'co3/co4', u'co4/co5', u'co5/co6', u'co6/co7', u'co7/co8', u'co8/co9', u'co9/co10', u'co10/co11', u'co11/co12', u'co12/co13']
Lambda whats it doing, first it split with "/" and select the 1st value and select the value after 1 index and convert to integer Lambda它做什么,首先用“/”拆分并选择第一个值并选择1个索引后的值并转换为整数
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