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How to check whether a file or directory exists?
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// exists returns whether the given file or directory exists
func exists(path string) (bool, error) {
_, err := os.Stat(path)
if err == nil { return true, nil }
if os.IsNotExist(err) { return false, nil }
return false, err
}
Edited to add error han...
django template display item value or empty string
...the question to better understand your answer.
– Victor Zamanian
Apr 20 '18 at 10:01
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boolean in an if statement
...a remark about code considering the way I check whether a variable is true or false in a school assignment.
14 Answers
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java: Class.isInstance vs Class.isAssignableFrom
...be true whenever the class represented by the clazz object is a superclass or superinterface of Foo.
clazz.isInstance(obj) will be true whenever the object obj is an instance of the class clazz.
That is:
clazz.isAssignableFrom(obj.getClass()) == clazz.isInstance(obj)
is always true so long as ...
Convert LocalDate to LocalDateTime or java.sql.Timestamp
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JodaTime
To convert JodaTime's org.joda.time.LocalDate to java.sql.Timestamp, just do
Timestamp timestamp = new Timestamp(localDate.toDateTimeAtStartOfDay().getMillis());
To convert JodaTime's org.joda.time.LocalDateTime to java.sql.Timestamp, just do
Tim...
Insert code into the page context using a content script
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Underlying cause:
Content scripts are executed in an "isolated world" environment.
Solution::
To access functions/variables of the page context ("main world") you have to inject the code that wants to access them into the page itself. Same thing if you want to expose your functions/variab...
Aborting a shell script if any command returns a non-zero value?
...ero exit value. A simple command is any command not part of an if, while, or until test, or part of an && or || list.
See the bash(1) man page on the "set" internal command for more details.
I personally start almost all shell scripts with "set -e". It's really annoying to have a script ...
Batch file to copy files from one folder to another folder
I have a storage folder on a network in which all users will store their active data on a server. Now that server is going to be replaced by a new one due to place problem so I need to copy sub folders files from the old server storage folder to new server storage folder. I have below ex:
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“var” or no “var” in JavaScript's “for-in” loop?
What's the correct way to write a for-in loop in JavaScript? The browser doesn't issue a complaint about either of the two approaches I show here. First, there is this approach where the iteration variable x is explicitly declared:
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Can virtual functions have default parameters?
If I declare a base class (or interface class) and specify a default value for one or more of its parameters, do the derived classes have to specify the same defaults and if not, which defaults will manifest in the derived classes?
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