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Immutable vs Mutable types
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What? Floats are immutable? But can't I do
x = 5.0
x += 7.0
print x # 12.0
Doesn't that "mut" x?
Well you agree strings are immutable right? But you can do the same thing.
s = 'foo'
s += 'bar'
print s # foobar
The value of the variable changes, but it changes by chang...
Getting a map() to return a list in Python 3.x
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802
Do this:
list(map(chr,[66,53,0,94]))
In Python 3+, many processes that iterate over iterable...
Python: Append item to list N times
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For immutable data types:
l = [0] * 100
# [0, 0, 0, 0, 0, ...]
l = ['foo'] * 100
# ['foo', 'foo', 'foo', 'foo', ...]
For values that are stored by reference and you may wish to modify later (like sub-lists, or dicts):
l = [{} for x in range(100)]
(Th...
Using jquery to get element's position relative to viewport
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edited Apr 17 '13 at 9:50
Pang
8,2181717 gold badges7373 silver badges111111 bronze badges
answered Oc...
How to find Unused Amazon EC2 Security groups
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edited Jul 1 at 20:15
Dherik
11.2k1010 gold badges7373 silver badges114114 bronze badges
answer...
Check if all elements in a list are identical
..., for Python 2.7 and (only s1, s4, s7, s9 should return True)
s1 = [1] * 5000
s2 = [1] * 4999 + [2]
s3 = [2] + [1]*4999
s4 = [set([9])] * 5000
s5 = [set([9])] * 4999 + [set([10])]
s6 = [set([10])] + [set([9])] * 4999
s7 = [1,1]
s8 = [1,2]
s9 = []
we get
| checkEqual1 | checkEqual2 | checkE...
What does %~d0 mean in a Windows batch file?
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The magic variables %n contains the arguments used to invoke the file: %0 is the path to the bat-file itself, %1 is the first argument after, %2 is the second and so on.
Since the arguments are often file paths, there is some additional syntax to extract parts of the path. ~d is drive, ~p is the...
Difference in System. exit(0) , System.exit(-1), System.exit(1 ) in Java
...seful to know if something went wrong and what went wrong.
Exit code is
0 when execution went fine;
1, -1, whatever != 0 when some error occurred, you can use different values for different kind of errors.
If I'm correct exit codes used to be just positive numbers (I mean in UNIX) and according...
How can I count the number of matches for a regex?
... following. (Starting from Java 9, there is a nicer solution)
int count = 0;
while (matcher.find())
count++;
Btw, matcher.groupCount() is something completely different.
Complete example:
import java.util.regex.*;
class Test {
public static void main(String[] args) {
String hel...
Scrolling a flexbox with overflowing content
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answered Feb 4 '14 at 0:59
Joseph SilberJoseph Silber
184k4747 gold badges324324 silver badges265265 bronze badges
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