我有两组同步的列表,如下所示: (同步我的意思是cal中的'A'在cpos中属于12,而mal中的'A'在mpos中属于11)
第一组
cpos = [12, 13, 14, 15]
cal = ['A', 'T', 'C', 'G']
第二组
mpos = [11, 12, 13, 16]
mal = ['A', 'T', 'T', 'G']
我想找到两个集合之间的匹配项,在这个例子中只有一个匹配项,cpos&cal 中的 13T 和 mpos&mal 中的 13T。
我写了这个脚本,但它似乎只是按索引比较值,因为匹配字符串是空的:
mat = []
for i in xrange(len(cpos)):
if mpos[i] == cpos[i] and mal[i] == cal[i]:
mat.append(cpos[i])
这是我想要得到的:
mat = [13]
有什么解决办法吗?
请您参考如下方法:
cpos = [12, 13, 14, 15]
cal = ['A', 'T', 'C', 'G']
mpos = [11, 12, 13, 16]
mal = ['A', 'T', 'T', 'G']
set1 = set(zip(cpos, cal))
set2 = set(zip(mpos, mal))
print set1 & set2
结果:
## set([(13, 'T')])
根据@Janne Karila 在下面的评论,以下内容会更有效率:
from itertools import izip
print set(izip(cpos, cal)).intersection(izip(mpos, mal))
时间:
import timeit
repeat = 1
setup = '''
num = 1000000
import random
import string
from itertools import izip
cpos = [random.randint(1, 100) for x in range(num)]
cal = [random.choice(string.letters) for x in range(num)]
mpos = [random.randint(1, 100) for x in range(num)]
mal = [random.choice(string.letters) for x in range(num)]
'''
# izip: 0.38 seconds (Python 2.7.2)
t = timeit.Timer(
setup = setup,
stmt = '''set(izip(cpos, cal)).intersection(izip(mpos, mal))'''
)
print "%.2f second" % (t.timeit(number=repeat))
# zip: 0.53 seconds (Python 2.7.2)
t = timeit.Timer(
setup = setup,
stmt = '''set(zip(cpos, cal)) & set(zip(mpos, mal))'''
)
print "%.2f second" % (t.timeit(number=repeat))
# Nested loop: 616 seconds (Python 2.7.2)
t = timeit.Timer(
setup = setup,
stmt = '''
mat = []
for i in xrange(len(cpos)):
for j in xrange(len(mpos)):
if mpos[j] == cpos[i] and mal[j] == cal[i]:
mat.append(mpos[j]) # or mat.append((mpos[j], mal[j])) ?
break
'''
)
print "%.2f seconds" % (t.timeit(number=repeat))
