我有一个很长的疑问。我想用Python将它分成几行。在JavaScript中实现这一点的一种方法是使用几个句子并用+运算符将它们连接起来（我知道，也许这不是最有效的方法，但我并不真正关心这个阶段的性能，只是代码的可读性）。例子：
var long_string = 'some text not important. just garbage to' +
'illustrate my example';
我尝试在Python中做类似的事情，但没有成功，所以我使用了\来拆分长字符串。然而，我不确定这是否是唯一/最好/最蟒蛇的做法。看起来很尴尬。实际代码：
query = 'SELECT action.descr as "action", '\
'role.id as role_id,'\
'role.descr as role'\
'FROM '\
'public.role_action_def,'\
'public.role,'\
'public.record_def, '\
'public.action'\
'WHERE role.id = role_action_def.role_id AND'\
'record_def.id = role_action_def.def_id AND'\
'action.id = role_action_def.action_id AND'\
'role_action_def.account_id = ' + account_id + ' AND'\
'record_def.account_id=' + account_id + ' AND'\
'def_id=' + def_id
其他人已经提到了圆括号方法，但我想补充一点，使用圆括号时，允许内联注释。
对每个片段的注释：
nursery_rhyme = (
'Mary had a little lamb,' # Comments are great!
'its fleece was white as snow.'
'And everywhere that Mary went,'
'her sheep would surely go.' # What a pesky sheep.
)
继续后不允许注释：
使用反斜杠行延续符（\）时，不允许使用注释。您将收到一个SyntaxError：一行接一行的连续字符错误。
nursery_rhyme = 'Mary had a little lamb,' \ # These comments
'its fleece was white as snow.' \ # are invalid!
'And everywhere that Mary went,' \
'her sheep would surely go.'
# => SyntaxError: unexpected character after line continuation character
Regex字符串的更好注释：
基于以下示例https://docs.python.org/3/library/re.html#re.VERBOSE,
a = re.compile(
r'\d+' # the integral part
r'\.' # the decimal point
r'\d*' # some fractional digits
)
# Using VERBOSE flag, IDE usually can't syntax highight the string comment.
a = re.compile(r"""\d + # the integral part
\. # the decimal point
\d * # some fractional digits""", re.X)
添加@Levon的答案。。。。
1.创建如下多行字符串：
paragraph = """this is a very
long string if I had the
energy to type more and more ..."""
print(paragraph)
输出：
'this is a very\n long string if I had the\n energy to type more and more ...'
此字符串将包含换行符和空格。因此，请移除它们。
2.使用正则表达式删除多余的空格
paragraph = re.sub('\s+', ' ', paragraph)
print(paragraph)
输出：
'this is a very long string if I had the energy to type more and more ...'
例如：
sql = ("select field1, field2, field3, field4 "
"from table "
"where condition1={} "
"and condition2={}").format(1, 2)
Output: 'select field1, field2, field3, field4 from table
where condition1=1 and condition2=2'
如果条件的值应该是字符串，可以这样做：
sql = ("select field1, field2, field3, field4 "
"from table "
"where condition1='{0}' "
"and condition2='{1}'").format('2016-10-12', '2017-10-12')
Output: "select field1, field2, field3, field4 from table where
condition1='2016-10-12' and condition2='2017-10-12'"
你说的是多行字符串吗？简单，使用三引号开始和结束它们。
s = """ this is a very
long string if I had the
energy to type more and more ..."""
您也可以使用单引号（当然，在开始和结束处有3个引号），并像对待任何其他字符串一样对待生成的字符串。
注意：与任何字符串一样，起始引号和结束引号之间的任何内容都将成为字符串的一部分，因此本示例有一个前导空格（如@root45所指出的）。此字符串还将包含空格和换行符。
即。，：
' this is a very\n long string if I had the\n energy to type more and more ...'
最后，您还可以在Python中构造如下的长行：
s = ("this is a very"
"long string too"
"for sure ..."
)
这将不包括任何额外的空格或换行符（这是一个故意的示例，显示跳过空格的效果）：
'this is a verylong string toofor sure ...'
不需要逗号，只需将要连接在一起的字符串放入一对括号中，并确保考虑到任何需要的空格和换行符。
我发现，当构建长字符串时，您通常会做一些类似于构建SQL查询的事情，在这种情况下，这是最好的：
query = ' '.join(( # Note double parentheses. join() takes an iterable
"SELECT foo",
"FROM bar",
"WHERE baz",
))
Levon的建议很好，但可能容易出错：
query = (
"SELECT foo"
"FROM bar"
"WHERE baz"
)
query == "SELECT fooFROM barWHERE baz" # Probably not what you want
