Pythonic way to create a long multi
I have a very long query. I would like to split it in several lines in Python. A way to do it in JavaScript would be using several sentences and joining them with a +
operator (I know, maybe it's not the most efficient way to do it, but I'm not really concerned about performance in this stage, just code readability). Example:
var long_string = 'some text not important. just garbage to' +
'illustrate my example';
I tried doing something similar in Python, but it didn't work, so I used to split the long string. However, I'm not sure if this is the only/best/pythonicest way of doing it. It looks awkward. Actual code:
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
Are you talking about multi-line strings? Easy, use triple quotes to start and end them.
s = """ this is a very
long string if I had the
energy to type more and more ..."""
You can use single quotes too (3 of them of course at start and end) and treat the resulting string s
just like any other string.
NOTE : Just as with any string, anything between the starting and ending quotes becomes part of the string, so this example has a leading blank (as pointed out by @root45). This string will also contain both blanks and newlines.
Ie,:
' this is a veryn long string if I had then energy to type more and more ...'
Finally, one can also construct long lines in Python like this:
s = ("this is a very"
"long string too"
"for sure ..."
)
which will not include any extra blanks or newlines (this is a deliberate example showing what the effect of skipping blanks will result in):
'this is a verylong string toofor sure ...'
No commas required, simply place the strings to be joined together into a pair of parenthesis and be sure to account for any needed blanks and newlines.
If you don't want a multiline string but just have a long single line string, you can use parentheses, just make sure you don't include commas between the string segments, then it will be a tuple.
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)
In a SQL statement like what you're constructing, multiline strings would also be fine. But if the extra whitespace a multiline string would contain would be a problem, then this would be a good way to achieve what you want.
Breaking lines by works for me. Here is an example:
longStr = "This is a very long string "
"that I wrote to help somebody "
"who had a question about "
"writing long strings in Python"
链接地址: http://www.djcxy.com/p/18490.html
上一篇: 使用strftime将python datetime转换为纪元
下一篇: Pythonic的方式来创建一个长的多