大约有 42,000 项符合查询结果（耗时：0.0337秒） [XML]
find() with nil when there are no records
...cue nil solution by mohamed-ibrahim? Seems more elegant than .where(email: params[:email]).first to me.
– Wylliam Judd
Jan 22 '18 at 22:07
1
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Using scp to copy a file to Amazon EC2 instance?
...onaws.com:~
Few notes for beginning:
Note the spaces between the three parameters given after the -i
scp stands for secure copy protocol. Knowing the words makes it easier to remember the command.
-i dictates that you need to give the .pem file as the next param. If there is no -i, than you do n...
'IF' in 'SELECT' statement - choose output value based on column values
...and other with a list of arguments, but ifnull invokes the coalesce with 2 parameters sql/item_cmpfunc.h 722: Item_func_ifnull(Item *a, Item *b) :Item_func_coalesce(a,b) {}
– Felipe Buccioni
Sep 1 '13 at 3:33
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How do I display a text file content in CMD?
...pe xxxx.txt
This displays the file in the current window. Maybe this has params you can use...
There is a similar question here: CMD.EXE batch script to display last 10 lines from a txt file
So there is a "more" command to display a file from the given line, or you can use the GNU Utilities for W...
Pandas DataFrame Groupby two columns and get counts
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There is no param called name in reset_index() in the current version of pandas: pandas.pydata.org/pandas-docs/stable/generated/…
– mmBs
Nov 25 '18 at 21:27
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setBackground vs setBackgroundDrawable (Android)
...hanging. They had "fill_parent" being changed to "match_parent" for layout params values. Both are exactly the same thing, pointing to the same value..
– android developer
Oct 31 '18 at 6:16
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Creating a JSON response using Django and Python
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@int_ua: just add json_dumps_params={"ensure_ascii": False} (requires Django 1.9 or newer)
– Martijn Pieters♦
Nov 9 '19 at 16:18
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Echo newline in Bash prints literal \n
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I think -e param doesn't exist on all *nix OS
– kenorb
Sep 4 '13 at 15:28
12
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How to do a logical OR operation in shell scripting
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From Bash Reference Manual → 3.4.2 Special Parameters
#
($#) Expands to the number of positional parameters in decimal.
Therefore, $# will always be either 0 or a bigger integer.
So if you want to do something whenever $# is either 0 or bigger than 1, you jus...
get dictionary value by key
...s true or false based on whether the key is found or not, and sets its out parameter to the corresponding value if the key is there.
If you want to check if the key is there or not and do something when it's missing, you need something like this:
bool hasValue = Data_Array.TryGetValue("XML_File", ...