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How to design a product table for many kinds of product where each product has many parameters
...is overkill. Class Table Inheritance would be my first choice.
Update 2019: The more I see people using JSON as a solution for the "many custom attributes" problem, the less I like that solution. It makes queries too complex, even when using special JSON functions to support them. It takes a lot...
Renaming files in a folder to sequential numbers
... let, and printf for the padding:
a=1
for i in *.jpg; do
new=$(printf "%04d.jpg" "$a") #04 pad to length of 4
mv -i -- "$i" "$new"
let a=a+1
done
using the -i flag prevents automatically overwriting existing files.
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How to list all installed packages and their versions in Python?
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Ashwini ChaudharyAshwini Chaudhary
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Constructing pandas DataFrame from values in variables gives “ValueError: If using all scalar values
...t;>> df = pd.DataFrame({'A': [a], 'B': [b]})
>>> df
A B
0 2 3
or use scalar values and pass an index:
>>> df = pd.DataFrame({'A': a, 'B': b}, index=[0])
>>> df
A B
0 2 3
share...
Why is null an object and what's the difference between null and undefined?
...rs♦
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answered Apr 29 '09 at 13:31
RobRob
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Why does int num = Integer.getInteger(“123”) throw NullPointerException?
... of the Puzzlers: Schlock and Awe (TS-5186), Josh Bloch and Neal Gafter's 2009 JavaOne Technical Session presentation. Here's the concluding slide:
The Moral
Strange and terrible methods lurk in libraries
Some have innocuous sounding names
If your code misbehaves
Mak...
What is more efficient: Dictionary TryGetValue or ContainsKey+Item?
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10 Answers
10
Active
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console.writeline and System.out.println
...mo {
public static void main(String[] args) {
String[] data = { "\u250C\u2500\u2500\u2500\u2500\u2500\u2510",
"\u2502Hello\u2502",
"\u2514\u2500\u2500\u2500\u2500\u2500\u2518" };
for (String s : data) {
System.out.println(s);
}
for (String s : data) {
S...
Meaning of “[: too many arguments” error from if [] (square brackets)
...:
VARIABLE=$(/some/command);
# returns "hello world"
if [ $VARIABLE == 0 ]; then
# fails as if you wrote:
# if [ hello world == 0 ]
fi
The same will be true for any function call that puts down a string containing spaces or other special characters.
Easy fix
Wrap the variable output i...
make an html svg object also a clickable link
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answered Jul 7 '12 at 10:59
Erik DahlströmErik Dahlström
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