I have a long string, which is basically a list like str="lamp, bag, mirror," (and other items)
I was wondering if I can add or subtract some items, in other programming languages I can easily do: str=str-"bag," and get str="lamp, mirror," this doesnt work in python (I'm using 2.7 on a W8 pc)
Is there a way to split the string across say "bag," and somehow use that as a subtraction? Then I still need to figure out how to add.
你也可以这样做
print "lamp, bag, mirror".replace("bag,","")
这个怎么样？
def substract(a, b):
return "".join(a.rsplit(b))
只要您使用格式正确的列表，您就可以这样做：
s0 = "lamp, bag, mirror"
s = s0.split(", ") # s is a list: ["lamp", "bag", "mirror"]
如果列表格式不正确，您可以按照@Lattyware 的建议执行以下操作：
s = [item.strip() for item in s0.split(',')]
现在删除元素：
s.remove("bag")
s
=> ["lamp", "mirror"]
无论哪种方式 - 要重建字符串，请使用join()：
", ".join(s)
=> "lamp, mirror"
另一种方法是使用replace()- 但要小心要替换的字符串，例如"mirror"末尾没有尾随,。
s0 = "lamp, bag, mirror"
s0.replace("bag, ", "")
=> "lamp, mirror"
您应该将您的字符串转换为字符串列表，然后执行您想要的操作。看
my_list="lamp, bag, mirror".split(',')
my_list.remove('bag')
my_str = ",".join(my_list)
from re import sub
def Str2MinusStr1 (str1, str2, n=1) :
return sub(r'%s' % (str2), '', str1, n)
Str2MinusStr1 ('aabbaa', 'a')
# result 'abbaa'
Str2MinusStr1 ('aabbaa', 'ab')
# result 'abaa'
Str2MinusStr1 ('aabbaa', 'a', 0)
# result 'bb'
# n = number of occurences.
# 0 means all, else means n of occurences.
# str2 can be any regular expression.
如果您有两个字符串，如下所示：
t1 = 'how are you'
t2 = 'How is he'
并且您想减去这两个字符串，那么您可以使用以下代码：
l1 = t1.lower().split()
l2 = t2.lower().split()
s1 = ""
s2 = ""
for i in l1:
if i not in l2:
s1 = s1 + " " + i
for j in l2:
if j not in l1:
s2 = s2 + " " + j
new = s1 + " " + s2
print new
输出将如下所示：
你是他吗
使用正则表达式示例：
import re
text = "lamp, bag, mirror"
word = "bag"
pattern = re.compile("[^\w]+")
result = pattern.split(text)
result.remove(word)
print ", ".join(result)
使用以下内容，您可以添加更多要删除的单词 ( ["bag", "mirror", ...])
(s0, to_remove) = ("lamp, bag, mirror", ["bag"])
s0 = ", ".join([x for x in s0.split(", ") if x not in to_remove])
=> "lamp, mirror"