使用max len

Question

我尝试将长串发送到覆盆子pi上的20x4 LCD显示器，这意味着4行中有20个字符。

要保持lcd上的文字可读，我希望在

上拆分

1. 空白
2. 特殊字符，如＆＃39;，＆＃39;，＆＃39;。＆＃39;，＆＃39;！＆＃39;，＆＃39;？＆＃39;等
3. Max line len of 20
4. Max word len of 20

我发现一些代码按字（空格）分割字符串，但我无法进一步...

s = "This is a very long string with many many many many and many more sentences and there is not one character that i can use to split by, just by number of words 1 2 3 12° C 3, ,5 ,6 .7 5 "
l = s.split()
n = 5
[' '.join(l[x:x+n]) for x in range(0, len(l), n)]

在这种情况下，两个单词可能是＆＃39; foobarfoobarfoobar foo＆＃39; ，其长度超过20个字符。

Answer 1

nice textwrap module in the standard library为您带来前90％。它主要在空格上分割（而不是在你的特殊字符上）。如果你真的需要拆分它们，你总是可以用whitesapce为它们加上后缀。

import textwrap
wrapper = textwrap.TextWrapper(width=20)
for line in wrapper.wrap(text):
    print line, len(line)

Answer 2

s = "longlongstuff [...]"
n = s.split() #whitespace
n = n.split(",")
n.flatten() #not sure about this.              transforms matrixes (and 3or more dimensional arrays) into one dimensional ones
n = n.split(".")
n.flatten()
#...
for i in range(len(n)):
    e = n[i]
    if len(e) > 20: #length longer than 20
         n[i] = [e[:20],e[19:]]
 n.flatten()
 "\n". join(n)

应该有点工作。小psydocode

Answer 3

您可以使用正则表达式在最近的单词边界处将换行符插入20个字符：

In [22]: print re.sub(r"(\b.{,20}\b)",r"\1"+"\n",s)
This is a very long 
string with many 
many many many and 
many more sentences 
and there is not one
 character that i 
can use to split by
, just by number of 
words 1 2 3 12° C 3
, ,5 ,6 .7 5 
foobarfoobarfoobar 
foo

如果你想更具体或添加更多逻辑，你也可以将lambda传递给sub：

In [106]: f = lambda x: x.group(1).strip()+",\n"

In [107]: print re.sub(r"(\b.{,20}\b)", f, s).rstrip(",\n")
This is a very long,
string with many,
many many many and,
many more sentences,
and there is not one,
character that i,
can use to split by,
, just by number of,
words 1 2 3 12° C 3,
, ,5 ,6 .7 5,
foobarfoobarfoobar,
foo