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How to determine whether a substring is in a different string
...d_sub_string(word, string):
len_word = len(word) #returns 3
for i in range(len(string)-1):
if string[i: i + len_word] == word:
return True
else:
return False
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Select rows of a matrix that meet a condition
... @neilfws What will be the solution if I want to define some values for a range of columns. for example df <- df[!which(df$ARID3A:df$YY1 == "U"),], here I want to remove those rows from my df where a range of columns (ARID3A: YY1) contains the value U.
– Newbie
...
Queue.Queue vs. collections.deque
...ue
import collections
q = collections.deque()
t0 = time.clock()
for i in xrange(100000):
q.append(1)
for i in xrange(100000):
q.popleft()
print 'deque', time.clock() - t0
q = Queue.Queue(200000)
t0 = time.clock()
for i in xrange(100000):
q.put(1)
for i in xrange(100000):
q.get()
pr...
Java HashMap performance optimization / alternative
...g lengths, from 1 to 10,000, and are fairly evenly distributed across that range, that this could be a very good hash function. But if your strings are all 1 or 2 characters, this would be a very bad hash function.
Edit: I should add: Every time you add a new entry, HashMap checks if this is a dupl...
Python using enumerate inside list comprehension
...yntax.
This list comprehension returns a list of tuples:
[(i,j) for i in range(3) for j in 'abc']
this a list of dicts:
[{i:j} for i in range(3) for j in 'abc']
a list of lists:
[[i,j] for i in range(3) for j in 'abc']
a syntax error:
[i,j for i in range(3) for j in 'abc']
Which is inco...
Convert Long into Integer
...situations, you might run into overflows (because a Long can store a wider range than an Integer).
Java 8 has a helper method that checks for overflow (you get an exception in that case):
Integer i = theLong == null ? null : Math.toIntExact(theLong);
...
Why dict.get(key) instead of dict[key]?
... includes looking up all the valid keys only)
def getway(d):
for i in range(100):
s = d.get(i)
def lookup(d):
for i in range(100):
s = d[i]
Now timing these two functions using timeit
>>> import timeit
>>> print(timeit.timeit("getway({i:i for i in range...
Getting the first and last day of a month, using a given DateTime object
...
DateTime structure stores only one value, not range of values. MinValue and MaxValue are static fields, which hold range of possible values for instances of DateTime structure. These fields are static and do not relate to particular instance of DateTime. They relate to D...
What is the “right” way to iterate through an array in Ruby?
...Loeb's comment), but I am saying that there is a sane way to expect this arrangement.
When I am dealing with arrays, I am focused on the elements in the array (not the index because the index is transitory). The method is each with index, i.e. each+index, or |each,index|, or |value,index|. This i...
Counting the Number of keywords in a dictionary in python
... comparison to whatever else your program is doing.
d = {x: x**2 for x in range(1000)}
len(d)
# 1000
len(d.keys())
# 1000
%timeit len(d)
# 41.9 ns ± 0.244 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)
%timeit len(d.keys())
# 83.3 ns ± 0.41 ns per loop (mean ± std. dev. of 7 ...