Python 在第二次出现字符后拆分文本
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Split text after the second occurrence of character
提问by DBS
I need to split text before the second occurrence of the '-' character. What I have now is producing inconsistent results. I've tried various combinations of rsplitand read through and tried other solutions on SO, with no results.
我需要在第二次出现“-”字符之前拆分文本。我现在所拥有的是产生不一致的结果。我尝试了各种组合rsplit并通读并尝试了其他解决方案，但没有结果。
Sample file name to split: 'some-sample-filename-to-split'returned in data.filename. In this case, I would only like to have 'some-sample'returned.
要拆分的示例文件名：'some-sample-filename-to-split'以data.filename. 在这种情况下，我只想'some-sample'回来。
fname, extname = os.path.splitext(data.filename)
file_label = fname.rsplit('/',1)[-1]
file_label2 = file_label.rsplit('-',maxsplit=3)
print(file_label2,'\n','---------------','\n')
回答by JRodDynamite
You can do something like this:
你可以这样做：
>>> a = "some-sample-filename-to-split"
>>> "-".join(a.split("-", 2)[:2])
'some-sample'
a.split("-", 2)will split the string upto the second occurrence of -.
a.split("-", 2)将字符串拆分到第二次出现-.
a.split("-", 2)[:2]will give the first 2 elements in the list. Then simply join the first 2 elements.
a.split("-", 2)[:2]将给出列表中的前 2 个元素。然后只需加入前 2 个元素。
OR
或者
You could use regular expression : ^([\w]+-[\w]+)
您可以使用正则表达式： ^([\w]+-[\w]+)
>>> import re
>>> reg = r'^([\w]+-[\w]+)'
>>> re.match(reg, a).group()
'some-sample'
EDIT:As discussed in the comments, here is what you need:
编辑：正如评论中所讨论的，这是您需要的：
def hyphen_split(a):
if a.count("-") == 1:
return a.split("-")[0]
else:
return "-".join(a.split("-", 2)[:2])
>>> hyphen_split("some-sample-filename-to-split")
'some-sample'
>>> hyphen_split("some-sample")
'some'
回答by Nuno André
A generic form to split a string into halves on the nth occurence of the separator would be:
在第 n 次出现分隔符时将字符串分成两半的通用形式是：
def split(strng, sep, pos):
strng = strng.split(sep)
return sep.join(strng[:pos]), sep.join(strng[pos:])
If posis negative it will count the occurrences from the end of string.
如果pos是负数，它将从字符串末尾计算出现次数。
>>> strng = 'some-sample-filename-to-split'
>>> split(strng, '-', 3)
('some-sample-filename', 'to-split')
>>> split(strng, '-', -4)
('some', 'sample-filename-to-split')
>>> split(strng, '-', 1000)
('some-sample-filename-to-split', '')
>>> split(strng, '-', -1000)
('', 'some-sample-filename-to-split')
回答by Mike Müller
You can use str.index():
您可以使用str.index()：
def hyphen_split(s):
pos = s.index('-')
try:
return s[:s.index('-', pos + 1)]
except ValueError:
return s[:pos]
test:
测试：
>>> hyphen_split("some-sample-filename-to-split")
'some-sample'
>>> hyphen_split("some-sample")
'some'
回答by Christian
You could use regular expressions:
您可以使用正则表达式：
import re
file_label = re.search('(.*?-.*?)-', fname).group(1)
