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In Python, what is the difference between “.append()” and “+= []”?
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In general case append will add one item to the list, while += will copy all elements of right-hand-side list into the left-hand-side list.
Update: perf analysis
Comparing bytecodes we can assume that append version wastes cycles in LOAD_ATTR + CALL_FUNCTION, and += version -- in BUILD_LIST. App...
Why can't Python parse this JSON data?
... You have [] when you should have {}:
[] are for JSON arrays, which are called list in Python
{} are for JSON objects, which are called dict in Python
Here's how your JSON file should look:
{
"maps": [
{
"id": "blabla",
"iscategorical": "0"
},
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Code coverage with Mocha
...ul is. Try the following, after you get your mocha tests to pass:
npm install nyc
Now, simply place the command nyc in front of your existing test command, for example:
{
"scripts": {
"test": "nyc mocha"
}
}
sha...
Pass Variables by Reference in Javascript
... it means that it's possible to pass a simple variable in such a way as to allow a function to modify that value in the calling context. So:
function swap(a, b) {
var tmp = a;
a = b;
b = tmp; //assign tmp to b
}
var x = 1, y = 2;
swap(x, y);
alert("x is " + x + ", y is " + y); // "...
How to select rows from a DataFrame based on column values?
...have multiple values you want to include, put them in a
list (or more generally, any iterable) and use isin:
print(df.loc[df['B'].isin(['one','three'])])
yields
A B C D
0 foo one 0 0
1 bar one 1 2
3 bar three 3 6
6 foo one 6 12
7 foo three 7 14
Note,...
Mysql: Select rows from a table that are not in another
How to select all rows in one table that do not appear on another?
8 Answers
8
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How to create local notifications?
...ication If application is in background then it displays BadgeNumber as 10 and with default notification sound.
This code works fine for iOS 7.x and below but for iOS 8 it will prompt following error on console:
Attempting to schedule a local notification with an alert but haven't received per...
warning: implicit declaration of function
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@Flimm, C99 and C89/C90 has different setting for this
– How Chen
Jan 15 '15 at 6:06
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How can I open a link in a new window?
I have a click handler for a specific link, inside that I want to do something similar to the following:
10 Answers
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How do I find out what keystore my JVM is using?
...les---> JAVA_HOME
Your server startup batch files.
In your import command -keystore cacerts (give full path to the above JRE here instead of just saying cacerts).
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