C++ 去除字符串中的空格
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Removing whitespaces inside a string
提问by Gandalf
I have a string lots\t of\nwhitespace\r\nwhich I have simplified but I still need to get rid of the other spaces in the string.
我有一个lots\t of\nwhitespace\r\n已经简化的字符串 ，但我仍然需要去掉字符串中的其他空格。
QString str = " lots\t of\nwhitespace\r\n ";
str = str.simplified();
I can do this erase_all(str, " ");in boost but I want to remain in qt.
我可以erase_all(str, " ");在 boost 中做到这一点，但我想留在 qt 中。
回答by arnt
str = str.simplified();
str.replace( " ", "" );
The first changes all of your whitespace characters to a single instance of ASCII 32, the second removes that.
第一个将所有空白字符更改为 ASCII 32 的单个实例，第二个将其删除。
回答by tonekk
Try this:
尝试这个：
str.replace(" ","");
回答by Terrabits
Option 1:
选项 1：
Simplify the white space, then remove it
简化空白，然后将其删除
Per the docs
根据文档
[
QString::simplified] Returns a string that has whitespace removed from the start and the end, and that has each sequence of internal whitespace replaced with a single space.
[
QString::simplified] 返回一个字符串，该字符串从开头和结尾删除了空格，并将每个内部空格序列替换为一个空格。
Once the string is simplified, the white spaces can easily be removed.
一旦字符串被简化，就可以轻松删除空格。
str.simplified().remove(' ')
Option 2:
选项 2：
Use a QRegExpto capture all types of white space in remove.
使用 aQRegExp来捕获remove.
QRegExp space("\s");
str.remove(space);
Notes
笔记
The OPs string has white space of different types (tab, carriage return, new line), all of which need to be removed. This is the tricky part.
QString::removewas introduced in Qt 5.6; prior to 5.6 removal can be achieved usingQString::replaceand replacing the white space with an empty string"".
OPs 字符串有不同类型的空格（制表符、回车符、换行符），所有这些都需要删除。这是棘手的部分。
QString::remove在 Qt 5.6 中引入；在 5.6 之前，可以使用QString::replace空字符串替换空格来实现删除""。
回答by Martin Hennings
You can omit the call to simplified()with a regex:
您可以simplified()使用正则表达式省略调用：
str.replace(QRegularExpression("\s+"), QString());
I don't have measured which method is faster. I guess this regex would perform worse.
我没有测量哪种方法更快。我猜这个正则表达式会表现得更糟。
