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In where shall I use isset() and !empty()
.....) contains some non-empty data.
To answer question 1 :
$str = '';
var_dump(isset($str));
gives
boolean true
Because the variable $str exists.
And question 2 :
You should use isset to determine whether a variable exists ; for instance, if you are getting some data as an array, you migh...
Stripping everything but alphanumeric chars from a string in Python
...ng.printable (part of the built-in string module). The use of compiled '[\W_]+' and pattern.sub('', str) was found to be fastest.
$ python -m timeit -s \
"import string" \
"''.join(ch for ch in string.printable if ch.isalnum())"
10000 loops, best of 3: 57.6 usec per loop
$ python -m tim...
How to replace multiple strings in a file using PowerShell
... PowerShell to continue parsing the expression on the next line:
$original_file = 'path\filename.abc'
$destination_file = 'path\filename.abc.new'
(Get-Content $original_file) | Foreach-Object {
$_ -replace 'something1', 'something1aa' `
-replace 'something2', 'something2bb' `
-re...
Rails: around_* callbacks
...classes/ActiveRecord/Callbacks.html , but don't understand when the around_* callbacks are triggered in relation to before_* and after_* .
...
How to detect if a script is being sourced
...
This seems to be portable between Bash and Korn:
[[ $_ != $0 ]] && echo "Script is being sourced" || echo "Script is a subshell"
A line similar to this or an assignment like pathname="$_" (with a later test and action) must be on the first line of the script or on the...
Installing python module within code
...upported by pip. Furthermore since pip v10, all code has been moved to pip._internal precisely in order to make it clear to users that programmatic use of pip is not allowed.
Use sys.executable to ensure that you will call the same pip associated with the current runtime.
import subprocess
import ...
How to read and write INI file with Python3?
...['DEFAULT']['path'] = '/var/shared/' # update
config['DEFAULT']['default_message'] = 'Hey! help me!!' # create
with open('FILE.INI', 'w') as configfile: # save
config.write(configfile)
You can find more at the official configparser documentation.
...
Mongoose query where value is not null
...ry The up-to-date doc about it, is here: mongoosejs.com/docs/api.html#query_Query-ne
– zeropaper
Jul 20 '14 at 7:52
Ho...
How to remove from a map while iterating it?
...begin(); it != m.cend() /* not hoisted */; /* no increment */)
{
if (must_delete)
{
m.erase(it++); // or "it = m.erase(it)" since C++11
}
else
{
++it;
}
}
Note that we really want an ordinary for loop here, since we are modifying the container itself. The range-based loop sh...
Why do we always prefer using parameters in SQL statements?
... the SQL statement is not going to be the same
– marc_s
Sep 21 '11 at 20:57
1
that means sql inje...