Python拆分删除分隔符？

Question

所以我有以下代码，在每个分号或 500 个字符之后放置一个 ~||~ 分隔符。这是有效的，但在找到分号时会删除它们。我看过这里，找到了答案，但我无法在我的代码中使用它。

chunk_len = 100
split_char = ';'
delim = ("~||~")
d = ";"
f = open(filename, "r")
text = f.read()
f.close()
lines = text.split(';')
for lines_idx, line in enumerate(lines):
    length = len(line)
    if length > chunk_len:
        chunks = [line[idx:idx+chunk_len]for idx in range(0,length,chunk_len)]
        lines[lines_idx] = delim.join(chunks)
new_text = delim.join(lines)
f = open(outputfile, 'w')
f.write(new_text)
f.close()

我在这里找到了这个解决方案，但我找不到将它合并到我的代码中的方法。对不起，重复的问题。

d = ">"
for line in all_lines:
    s =  [e+d for e in line.split(d) if e != ""]

Answer 1

如果我正确理解了您的问题，那么您真正想要做的是在每个分号和每 500 个字符后插入您自己的分隔符。尝试分两步进行：

with open(filename, "r") as fi: # read in file using "with" statement
    text = fi.read()

block_size = 500            # sets how many characters separate new_delim
old_delim = ";"             # character we are adding the new delimiter to
new_delim = "~||~"          # this will be inserted every block_size characters
del_length = len(new_delim) # store length to prevent repeated calculations

for i in xrange(len(line)/block_size): 
    # calculate next index where the new delimiter should be inserted
    index = i*block_size + i*del_length + block_size

    # construct new string with new delimiter at the given index        
    text = "{0}{0}{1}".format(text[:index], new_delim, text[index:]) 

replacement_delim = old_delim + new_delim # old_delim will be replaced with this

with open(outputfile, 'w') as fo:
    # write out new string with new delimiter appended to each semicolon
    fo.write(text.replace(old_delim, replacement_delim))

如果分号恰好出现在 500 个字符的倍数处，您的两个特殊分隔符可能会彼此相邻。此外，如果您的字符串中正好有多个 block_size 字符，那么您将在字符串的末尾有分隔符。

此外，如果您正在读取很长的文件，这可能不是最好的方法。For 循环会在每次插入分隔符时创建一个全新的字符串。

这种方法使 split 方法对分隔符的处理成为一个空点。

Answer 2

改变

lines = text.split(';')

到

lines = filter(None,re.split('([^;]+;)',text))

这应该保留分号......或者像其他答案一样稍后添加它

Answer 3

split() 拆分字符串并删除分隔符，您只需将其重新添加即可。我在您的循环中执行以下操作： line = line + d

chunk_len = 100
split_char = ';'
delim = ("~||~")
d = ";"
f = open(filename, "r")
text = f.read()
f.close()
lines = text.split(';')
for lines_idx, line in enumerate(lines):
    line = line + d  #NEW LINE ADDED HERE
    length = len(line)
    if length > chunk_len:
        chunks = [line[idx:idx+chunk_len]for idx in range(0,length,chunk_len)]
        lines[lines_idx] = delim.join(chunks)
new_text = delim.join(lines)
f = open(outputfile, 'w')
f.write(new_text)
f.close()