[英]Unique items in python list
I am trying to make a unique collection of dates in a Python list. 我试图在Python列表中创建一个独特的日期集合。
Only add a date to the collection if it not already present in the collection. 仅在集合中尚未存在日期时才添加日期。
timestamps = []
timestamps = [
'2011-02-22', '2011-02-05', '2011-02-04', '2010-12-14', '2010-12-13',
'2010-12-12', '2010-12-11', '2010-12-07', '2010-12-02', '2010-11-30',
'2010-11-26', '2010-11-23', '2010-11-22', '2010-11-16']
date = "2010-11-22"
if date not in timestamps:
timestamps.append(date)
How would I sort the list? 我该如何排序?
You can use sets for this. 你可以使用套装。
date = "2010-11-22"
timestamps = set(['2011-02-22', '2011-02-05', '2011-02-04', '2010-12-14', '2010-12-13', '2010-12-12', '2010-12-11', '2010-12-07', '2010-12-02', '2010-11-30', '2010-11-26', '2010-11-23', '2010-11-22', '2010-11-16'])
#then you can just update it like so
timestamps.update(['2010-11-16']) #if its in there it does nothing
timestamps.update(['2010-12-30']) # it does add it
This code will effectively do nothing. 这段代码实际上什么都不做。 You are referencing the same variable twice (
timestamps
). 您正在引用相同的变量两次(
timestamps
)。
So you would have to make two seperate lists: 所以你必须制作两个单独的列表:
unique_timestamps= []
timestamps = ['2011-02-22', '2011-02-05', '2011-02-04', '2010-12-14', '2010-12-13', '2010-12-12', '2010-12-11', '2010-12-07', '2010-12-02', '2010-11-30', '2010-11-26', '2010-11-23', '2010-11-22', '2010-11-16']
date="2010-11-22"
if(date not in timestamps):
unique_timestamps.append(date)
Your condition seems to be correct. 你的病情似乎是正确的。 If you do not care about the order of the dates though, it might be easier to use a set instead of a list.
如果您不关心日期的顺序,则使用集合而不是列表可能更容易。 You would not need any
if
in this case: 你不需要任何
if
在这种情况下:
timestamps = set(['2011-02-22', '2011-02-05', '2011-02-04', '2010-12-14',
'2010-12-13', '2010-12-12', '2010-12-11', '2010-12-07',
'2010-12-02', '2010-11-30', '2010-11-26', '2010-11-23',
'2010-11-22', '2010-11-16'])
timesteps.add("2010-11-22")
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