大约有 3,517 项符合查询结果（耗时：0.0107秒） [XML]
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 ...
Convert hex string to int
...
//Method for Smaller Number Range:
Integer.parseInt("abc",16);
//Method for Bigger Number Range.
Long.parseLong("abc",16);
//Method for Biggest Number Range.
new BigInteger("abc",16);
...
What is the correct SQL type to store a .Net Timespan with values > 24:00:00?
...Server (i.e. via T-SQL) and SQL Server is prior to 2016, depending on your range and precision needs, it may not be practical to store them as milliseconds (not to mention Ticks) because the Int Type returned by DateDiff (vs. the BigInt from SS 2016+'s DateDiff_Big) overflows after ~24 days worth of...
How to convert list of tuples to multiple lists?
...
from timeit import timeit
setup_string='''\
N = 2000000
xs = list(range(1, N))
ys = list(range(N+1, N*2))
zs = list(zip(xs, ys))
from __main__ import t1, t2, t3
'''
print(f'zip:\t\t{timeit('t1(zs)', setup=setup_string, number=1000)}')
print(f'append:\t\t{timeit('t2(zs)', setup=setup...
How to map atan2() to degrees 0-360
...ame value.
Negative: -180 to -1
Using mod here will return values in the range of 180 and 359 degrees.
Special cases: 0 and 360
Using mod means that 0 is returned, making this a safe 0-359 degrees solution.
share
...