假设我有一个列表:
main_list = ['bacon', 'cheese', 'milk', 'cake', 'tomato']
另一个列表:
second_list = ['cheese', 'tomato']
我如何从主列表中删除所有在第二个列表中找到的元素?
new_array = [x for x in main_array if x not in second_array]
然而,对于大型列表来说,这种方式性能并不理想。您可以通过使用一个集合来优化second_array
:second_array = set(second_array)
new_array = [x for x in main_array if x not in second_array]
如果项目的顺序不重要,您可以在两个数组中都使用一个 set:
new_array = list(set(main_array) - set(second_array))
如果顺序不重要,您可以使用集合:
>>> main_array = ['bacon', 'cheese', 'milk', 'cake', 'tomato']
>>> second_array = ['cheese', 'tomato']
>>> set(main_array) & set(second_array)
set(['tomato', 'cheese'])
这里我们使用交集运算符&
。如果您只想要第二个列表中不存在的项目,我们可以使用差集-
:
>>> set(main_array) - set(second_array)
set(['cake', 'bacon', 'milk'])
main_array = set(['bacon', 'cheese', 'milk', 'cake', 'tomato'])
second_array = (['cheese', 'tomato'])
main_array.difference(second_array)
>>> set(['bacon', 'cake', 'milk'])
main_array.intersection(second_array)
>>> set(['cheese', 'tomato'])
l = [u'SQOOP', u'SOLR', u'SLIDER', u'SFTP', u'PIG', u'NODEMANAGER', u'JSQSH', u'HCAT', u'HBASE_REGIONSERVER', u'GANGLIA_MONITOR', u'FLUME_HANDLER', u'DATANODE', u'BIGSQL_WORKER']
p = [u'SQOOP', u'SOLR', u'SLIDER', u'SFTP']
l = [i for i in l if i not in [j for j in p]]
print l
[u'PIG', u'NODEMANAGER', u'JSQSH', u'HCAT', u'HBASE_REGIONSERVER', u'GANGLIA_MONITOR', u'FLUME_HANDLER', u'DATANODE', u'BIGSQL_WORKER']
second_array
转换成集合,以优化维持顺序的变体:second_set = set(second_array); new_array = [x for x in main_array if x not in second_set]
- roskakori