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Detect if value is number in MySQL
...('12.e-5'),('3.5e+6'),('a'),('e6'),('+e0');
select
col1,
col1 + 0 as casted,
col1 REGEXP '^[+-]?[0-9]*([0-9]\\.|[0-9]|\\.[0-9])[0-9]*(e[+-]?[0-9]+)?$' as isNumeric
from myTable;
Result:
col1 | casted | isNumeric
-------|---------|----------
00.00 | 0 | 1
+1 | 1...
Why use symbols as hash keys in Ruby?
... basically "immutable strings" .. that means that they can not be changed, and it implies that the same symbol when referenced many times throughout your source code, is always stored as the same entity, e.g. has the same object id.
Strings on the other hand are mutable, they can be changed anytim...
php is null or empty?
... @Robert: A string not starting with digits is converted to 0 when cast to a string: codepad.org/qi40SG3E. So (int)"php" == 0.
– Felix Kling
Nov 27 '13 at 21:58
...
Create empty file using python [duplicate]
...fter the open() statement finished - but it's cleaner to do it explicitely and relying on CPython-specific behaviour is not good either.
In case you want touch's behaviour (i.e. update the mtime in case the file exists):
import os
def touch(path):
with open(path, 'a'):
os.utime(path, N...
Why is the apt-get function not working in the terminal on Mac OS X v10.9 (Mavericks)?
I was watching this , and, as you can see, the first command I am told to put in is:
5 Answers
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Excluding directories in os.walk
I'm writing a script that descends into a directory tree (using os.walk()) and then visits each file matching a certain file extension. However, since some of the directory trees that my tool will be used on also contain sub directories that in turn contain a LOT of useless (for the purpose of thi...
Automatically remove Subversion unversioned files
...The other solution from bellow svn cleanup --remove-unversioned is better. And it is for Subversion 1.9.0 (this version is from 2015). It is stable and standar.
– tres.14159
Nov 21 '18 at 8:19
...
Conditional import of modules in Python
...mport simplejson as json as it is likely a newer (faster) version of the standard json module.
– Seppo Erviälä
Oct 20 '12 at 17:07
...
How can mixed data types (int, float, char, etc) be stored in an array?
... x = r;
x.val = 25.0;
}
integer g = { INT, 100 };
record rg = g;
Up-casting and down-casting.
Edit: One gotcha to be aware of is if you're constructing one of these with C99 designated initializers. All member initializers should be through the same union member.
record problem = { .tag ...
Correct approach to global logging in Golang
...
Create a single log.Logger and pass it around?
That is possible. A log.Logger can be used concurrently from multiple goroutines.
Pass around a pointer to that log.Logger?
log.New returns a *Logger which is usually an indication that yo...