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Python initializing a list of lists [duplicate]
...instance.
To make a list of 3 different lists, do this:
x = [[] for i in range(3)]
This gives you 3 separate instances of [], which is what you want
[[]]*n is similar to
l = []
x = []
for i in range(n):
x.append(l)
While [[] for i in range(3)] is similar to:
x = []
for i in range(n):
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Python loop that also accesses previous and next values
... edited Apr 27 '16 at 13:32
Trang Oul
12966 bronze badges
answered Jun 18 '09 at 10:28
Hank GayHank Gay
...
How to get all possible combinations of a list’s elements?
...oop through all lengths "L":
import itertools
stuff = [1, 2, 3]
for L in range(0, len(stuff)+1):
for subset in itertools.combinations(stuff, L):
print(subset)
Or -- if you want to get snazzy (or bend the brain of whoever reads your code after you) -- you can generate the chain of "co...
How to Get the Title of a HTML Page Displayed in UIWebView?
...g:NSASCIIStringEncoding error:nil];
NSString * start = @"<title>";
NSRange range1 = [htmlCode rangeOfString:start];
NSString * end = @"</title>";
NSRange range2 = [htmlCode rangeOfString:end];
NSString * subString = [htmlCode substringWithRange:NSMakeRange(range1.location + 7, range2.l...
How to open a specific port such as 9090 in Google Compute Engine
...allow tcp:9090 --source-tags=<list-of-your-instances-names> --source-ranges=0.0.0.0/0 --description="<your-description-here>"
This will open the port 9090 for the instances that you name. Omitting --source-tags and --source-ranges will apply the rule to all instances. More details are ...
Delete element in a slice
...
Don't you get out of range exception if i is the last element from slice? a = append(a[:i], a[i+1:]...)
– themihai
May 21 '15 at 8:13
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Split a python list into other “sublists” i.e smaller lists [duplicate]
...
I'd say
chunks = [data[x:x+100] for x in range(0, len(data), 100)]
If you are using python 2.x instead of 3.x, you can be more memory-efficient by using xrange(), changing the above code to:
chunks = [data[x:x+100] for x in xrange(0, len(data), 100)]
...
How would you compare jQuery objects?
...
You need to compare the raw DOM elements, e.g.:
if ($(this).parent().get(0) === $('body').get(0))
or
if ($(this).parent()[0] === $('body')[0])
share
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Generate random int value from 3 to 6
... What if I have to generate random number between 1 and 27? i.e. range greater then 9?
– somegeek
Dec 19 '17 at 9:26
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I want to exception handle 'list index out of range.'
...
for i in range (1, len(list))
try:
print (list[i])
except ValueError:
print("Error Value.")
except indexError:
print("Erorr index")
except :
print('error ')
...