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jQuery: checking if the value of a field is null (empty)
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170
The value of a field can not be null, it's always a string value.
The code will check if the st...
How to get a substring of text?
I have text with length ~700. How do I get only ~30 of its first characters?
5 Answers
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How to express infinity in Ruby?
...y 1.8.6, 1.8.7, and 1.9.2 you have Float.infinite?.
PositiveInfinity = +1.0/0.0
=> Infinity
NegativeInfinity = -1.0/0.0
=> -Infinity
CompleteInfinity = NegativeInfinity..PositiveInfinity
=> -Infinity..Infinity
*I've verified this in Ruby 1.8.6 and 1.9.2
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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...
Prepend a level to a pandas MultiIndex
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cs95
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answered Feb 7 '17 at 16:11
okartalokartal
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How to make an array of arrays in Java
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answered Jan 24 '11 at 10:54
Jon SkeetJon Skeet
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Blocks on Swift (animateWithDuration:animations:completion:)
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202
the completion parameter in animateWithDuration takes a block which takes one boolean parameter...
Time complexity of Sieve of Eratosthenes algorithm
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answered Apr 6 '10 at 5:17
ShreevatsaRShreevatsaR
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What Does 'Then' Really Mean in CasperJS
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edited Nov 10 '12 at 7:05
answered Aug 14 '12 at 17:51
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Converting between datetime, Timestamp and datetime64
... np
>>> dt = datetime.utcnow()
>>> dt
datetime.datetime(2012, 12, 4, 19, 51, 25, 362455)
>>> dt64 = np.datetime64(dt)
>>> ts = (dt64 - np.datetime64('1970-01-01T00:00:00Z')) / np.timedelta64(1, 's')
>>> ts
1354650685.3624549
>>> datetime.utcfromt...