Python 如何减去两个字符串？
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How to subtract two strings?
提问by max smith
I have a long string, which is basically a list like str="lamp, bag, mirror,"(and other items)
我有一个很长的字符串，它基本上是一个类似str="lamp, bag, mirror,"（和其他项目）的列表
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)
我想知道我是否可以添加或减去一些项目，在其他编程语言中我可以轻松做到：str=str-"bag,"并且str="lamp, mirror,"在 python 中不起作用（我在 W8 pc 上使用 2.7）
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.
有没有办法将字符串拆分为“包”，然后以某种方式将其用作减法？然后我还需要弄清楚如何添加。
回答by óscar López
You can do this as long as you use well-formed lists:
只要您使用格式良好的列表，就可以执行此操作：
s0 = "lamp, bag, mirror"
s = s0.split(", ") # s is a list: ["lamp", "bag", "mirror"]
If the list is not well-formed, you can do as follows, as suggested by @Lattyware:
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(',')]
Now to delete the element:
现在删除元素：
s.remove("bag")
s
=> ["lamp", "mirror"]
Either way - to reconstruct the string, use join():
无论哪种方式 - 要重建字符串，请使用join()：
", ".join(s)
=> "lamp, mirror"
A different approach would be to use replace()- but be careful with the string you want to replace, for example "mirror"doesn't have a trailing ,at the end.
一种不同的方法是使用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"
回答by dare
you should convert your string to a list of string then do what you want. look
您应该将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)
回答by Joran Beasley
you could also just do
你也可以这样做
print "lamp, bag, mirror".replace("bag,","")
回答by badc0re
Using regular expression example:
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)
回答by Zaka Elab
How about this?:
这个怎么样？：
def substract(a, b):
return "".join(a.rsplit(b))
回答by Rohan Amrute
If you have two strings like below:
如果你有两个像下面这样的字符串：
t1 = 'how are you'
t2 = 'How is he'
and you want to subtract these two strings then you can use the below code:
如果您想减去这两个字符串，则可以使用以下代码：
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
Output will be like:
输出将类似于：
are you is he
你是他吗
回答by J. Doe
Using the following you can add more words to remove (["bag", "mirror", ...])
使用以下内容，您可以添加更多单词以删除 ( ["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"
回答by Dengs
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.
