给出这样一个列表:
mylist = ["name", "state", "name", "city", "name", "zip", "zip"]
我想通过附加一个数字来重命名重复项,以获得以下结果:
mylist = ["name1", "state", "name2", "city", "name3", "zip1", "zip2"]
我不想更改原始列表的顺序。针对此related Stack Overflow question建议的解决方案对列表进行排序,我不想这样做。
答案 0 :(得分:12)
我的解决方案map
和lambda
:
print map(lambda x: x[1] + str(mylist[:x[0]].count(x[1]) + 1) if mylist.count(x[1]) > 1 else x[1], enumerate(mylist))
更传统的形式
newlist = []
for i, v in enumerate(mylist):
totalcount = mylist.count(v)
count = mylist[:i].count(v)
newlist.append(v + str(count + 1) if totalcount > 1 else v)
最后一个
[v + str(mylist[:i].count(v) + 1) if mylist.count(v) > 1 else v for i, v in enumerate(mylist)]
答案 1 :(得分:11)
我就是这样做的。
mylist = ["name", "state", "name", "city", "name", "zip", "zip"]
from collections import Counter # Counter counts the number of occurrences of each item
counts = Counter(mylist) # so we have: {'name':3, 'state':1, 'city':1, 'zip':2}
for s,num in counts.items():
if num > 1: # ignore strings that only appear once
for suffix in range(1, num + 1): # suffix starts at 1 and increases by 1 each time
mylist[mylist.index(s)] = s + str(suffix) # replace each appearance of s
编辑:这是一个单行,但订单不保留。
[s + str(suffix) if num>1 else s for s,num in Counter(mylist).items() for suffix in range(1, num+1)]
# Produces: ['zip1', 'zip2', 'city', 'state', 'name1', 'name2', 'name3']
答案 2 :(得分:5)
由于count
为O(n^2)
,因此在每个元素上调用count
的任何方法都将导致O(n)
。你可以这样做:
# not modifying original list
from collections import Counter
mylist = ["name", "state", "name", "city", "name", "zip", "zip"]
counts = {k:v for k,v in Counter(mylist).items() if v > 1}
newlist = mylist[:]
for i in reversed(range(len(mylist))):
item = mylist[i]
if item in counts and counts[item]:
newlist[i] += str(counts[item])
counts[item]-=1
print(newlist)
# ['name1', 'state', 'name2', 'city', 'name3', 'zip1', 'zip2']
# modifying original list
from collections import Counter
mylist = ["name", "state", "name", "city", "name", "zip", "zip"]
counts = {k:v for k,v in Counter(mylist).items() if v > 1}
for i in reversed(range(len(mylist))):
item = mylist[i]
if item in counts and counts[item]:
mylist[i] += str(counts[item])
counts[item]-=1
print(mylist)
# ['name1', 'state', 'name2', 'city', 'name3', 'zip1', 'zip2']
这应该是O(n)
。
mylist.index(s)
会导致O(n^2)
mylist = ["name", "state", "name", "city", "name", "zip", "zip"]
from collections import Counter
counts = Counter(mylist)
for s,num in counts.items():
if num > 1:
for suffix in range(1, num + 1):
mylist[mylist.index(s)] = s + str(suffix)
每个元素 count(x[1])
会导致O(n^2)
每个元素也会多次使用它以及列表切片。
print map(lambda x: x[1] + str(mylist[:x[0]].count(x[1]) + 1) if mylist.count(x[1]) > 1 else x[1], enumerate(mylist))
答案 3 :(得分:4)
这是一个非常简单的O(n)
解决方案。只需遍历列表中存储元素索引的列表即可。如果我们之前看过这个元素,请先使用存储的数据来附加出现值。
这种方法只需再创建一个字典进行回顾即可解决问题。避免进行预测,这样我们就不会创建临时列表切片。
mylist = ["name", "state", "name", "city", "city", "name", "zip", "zip", "name"]
dups = {}
for i, val in enumerate(mylist):
if val not in dups:
# Store index of first occurrence and occurrence value
dups[val] = [i, 1]
else:
# Special case for first occurrence
if dups[val][1] == 1:
mylist[dups[val][0]] += str(dups[val][1])
# Increment occurrence value, index value doesn't matter anymore
dups[val][1] += 1
# Use stored occurrence value
mylist[i] += str(dups[val][1])
print mylist
# ['name1', 'state', 'name2', 'city1', 'city2', 'name3', 'zip1', 'zip2', 'name4']
答案 4 :(得分:2)
Rick Teachey answer的列表理解版本,“双线”:
from collections import Counter
m = ["name", "state", "name", "city", "name", "zip", "zip"]
d = {a:list(range(1, b+1)) if b>1 else '' for a,b in Counter(m).items()}
[i+str(d[i].pop(0)) if len(d[i]) else i for i in m]
#['name1', 'state', 'name2', 'city', 'name3', 'zip1', 'zip2']
答案 5 :(得分:1)
您可以使用哈希表来解决此问题。定义字典d。 key是字符串,值是(first_time_index_in_the_list,times_of_appearance)。每次看到单词时,只需检查字典,如果值为2,则使用first_time_index_in_the_list将“1”附加到第一个元素,并将times_of_appearance附加到当前元素。如果大于2,只需将times_of_appearance附加到当前元素。
答案 6 :(得分:1)
不那么花哨的东西。
from collections import defaultdict
mylist = ["name", "state", "name", "city", "name", "zip", "zip"]
finalList = []
dictCount = defaultdict(int)
anotherDict = defaultdict(int)
for t in mylist:
anotherDict[t] += 1
for m in mylist:
dictCount[m] += 1
if anotherDict[m] > 1:
finalList.append(str(m)+str(dictCount[m]))
else:
finalList.append(m)
print finalList