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Whether a variable is undefined [duplicate]
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jQuery.val() and .text() will never return 'undefined' for an empty selection. It always returns an empty string (i.e. ""). .html() will return null if the element doesn't exist though.You need to do:
if(page_name != '')
For other va...
How to process each line received as a result of grep command
... have a number of lines retrieved from a file after running the grep command as follows:
7 Answers
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What are some uses of decltype(auto)?
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You can also use decltype(auto) in other contexts, e.g. the draft Standard N3936 also states
7.1.6.4 auto specifier [dcl.spec.auto]
1 The auto and decltype(auto) type-specifiers designate a placeholder
type that will be replaced later, either by deduction from an
initializer or by ...
“unadd” a file to svn before commit
I was in the middle of doing a recursive svn add/commit, and a folder which did not have the proper ignore properties was included. I've got about 100 uploaded binary files versioned now, but I haven't committed yet.
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Display two files side by side
...n use pr to do this, using the -m flag to merge the files, one per column, and -t to omit headers, eg.
pr -m -t one.txt two.txt
outputs:
apple The quick brown fox..
pear foo
longer line than the last two bar
last line ...
With GitHub how do I push all branches when adding an existing repo?
...t push --tags
would really push everything. See also "Set up git to pull and push all branches".
Don't forget the --dry-run option to make some test before actually pushing everything.
See also GitHub help "Working with remotes" to set your origin to your GitHub remote repo.
As mentioned in "Ho...
How do I show a MySQL warning that just happened?
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You can also set the command line to always display warnings after a query using \W
You can switch them off again with \w
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Matplotlib: “Unknown projection '3d'” error
I just installed matplotlib and am trying to run one of there example scripts. However I run into the error detailed below. What am I doing wrong?
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How do you check that a number is NaN in JavaScript?
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If i were you i would assign it to a variable and , use condition variable !== variable . As it is laid out in specs tc39.github.io/ecma262/#sec-isnan-number
– allsyed
Jul 11 '16 at 5:43
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Sending command line arguments to npm script
...rgs to npm run as of npm 2.0.0
The syntax is as follows:
npm run <command> [-- <args>]
Note the necessary --. It is needed to separate the params passed to npm command itself and params passed to your script.
So if you have in package.json
"scripts": {
"grunt": "grunt",
"ser...