我试图采取一个字符串,并将其附加到每个字符串包含在一个列表,然后有一个新的列表与完成的字符串。例子:
list1 = ['foo', 'fob', 'faz', 'funk']
string = 'bar'
*magic*
list2 = ['foobar', 'fobbar', 'fazbar', 'funkbar']
我尝试了for循环,并尝试了列表理解,但它是垃圾。一如既往,任何帮助,非常感谢。
我试图采取一个字符串,并将其附加到每个字符串包含在一个列表,然后有一个新的列表与完成的字符串。例子:
list1 = ['foo', 'fob', 'faz', 'funk']
string = 'bar'
*magic*
list2 = ['foobar', 'fobbar', 'fazbar', 'funkbar']
我尝试了for循环,并尝试了列表理解,但它是垃圾。一如既往,任何帮助,非常感谢。
当前回答
以防万一
list = ['foo', 'fob', 'faz', 'funk']
string = 'bar'
for i in range(len(list)):
list[i] += string
print(list)
其他回答
list2 = ['%sbar' % (x,) for x in list]
不要用list作为名字;它隐藏内置类型。
以python的方式运行下面的实验:
[s + mystring for s in mylist]
似乎比明显使用for循环快35%:
i = 0
for s in mylist:
mylist[i] = s+mystring
i = i + 1
实验
import random
import string
import time
mystring = '/test/'
l = []
ref_list = []
for i in xrange( 10**6 ):
ref_list.append( ''.join(random.choice(string.ascii_lowercase) for i in range(10)) )
for numOfElements in [5, 10, 15 ]:
l = ref_list*numOfElements
print 'Number of elements:', len(l)
l1 = list( l )
l2 = list( l )
# Method A
start_time = time.time()
l2 = [s + mystring for s in l2]
stop_time = time.time()
dt1 = stop_time - start_time
del l2
#~ print "Method A: %s seconds" % (dt1)
# Method B
start_time = time.time()
i = 0
for s in l1:
l1[i] = s+mystring
i = i + 1
stop_time = time.time()
dt0 = stop_time - start_time
del l1
del l
#~ print "Method B: %s seconds" % (dt0)
print 'Method A is %.1f%% faster than Method B' % ((1 - dt1/dt0)*100)
结果
Number of elements: 5000000
Method A is 38.4% faster than Method B
Number of elements: 10000000
Method A is 33.8% faster than Method B
Number of elements: 15000000
Method A is 35.5% faster than Method B
这里有一个简单的答案,用熊猫。
import pandas as pd
list1 = ['foo', 'fob', 'faz', 'funk']
string = 'bar'
list2 = (pd.Series(list1) + string).tolist()
list2
# ['foobar', 'fobbar', 'fazbar', 'funkbar']
my_list = ['foo', 'fob', 'faz', 'funk']
string = 'bar'
my_new_list = [x + string for x in my_list]
print my_new_list
这将打印:
['foobar', 'fobbar', 'fazbar', 'funkbar']
以防万一
list = ['foo', 'fob', 'faz', 'funk']
string = 'bar'
for i in range(len(list)):
list[i] += string
print(list)