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What is an undefined reference/unresolved external symbol error and how do I fix it?
...rsal-character-name
in a character literal or a non-raw string literal, is converted to
the corresponding member of the execution character set; [SNIP]
Adjacent string literal tokens are concatenated.
White-space characters separating tokens are no longer significant. Each preprocessing token is con...
Is there a Max function in SQL Server that takes two values like Math.Max in .NET?
... @val2))
Edit: If you're dealing with very large numbers you'll have to convert the value variables into bigint in order to avoid an integer overflow.
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Can't import my own modules in Python
...would have to mess with your path. This can be done within Python:
import sys
sys.path.append("..")
from myapp import SomeObject
though that is generally not recommended.
In general, if you want other people to use your Python package, you should use distutils to create a setup script. That way,...
How to convert index of a pandas dataframe into a column?
This seems rather obvious, but I can't seem to figure out how to convert an index of data frame to a column?
7 Answers
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What is “lifting” in Scala?
...e, suppose you have a function which returns an IO[Stream[A]]. This can be converted to the monad transformer StreamT[IO, A]. Now you may wish to "lift" some other value an IO[B] perhaps to that it is also a StreamT. You could either write this:
StreamT.fromStream(iob map (b => Stream(b)))
Or ...
SQL query to group by day
...
actually this depends on what DBMS you are using but in regular SQL convert(varchar,DateColumn,101) will change the DATETIME format to date (one day)
so:
SELECT
sum(amount)
FROM
sales
GROUP BY
convert(varchar,created,101)
the magix number 101 is what date format it is con...
How to merge dictionaries of dictionaries?
... recursive function is easiest:
def merge(a, b, path=None):
"merges b into a"
if path is None: path = []
for key in b:
if key in a:
if isinstance(a[key], dict) and isinstance(b[key], dict):
merge(a[key], b[key], path + [str(key)])
elif a[k...
Convert pandas timezone-aware DateTimeIndex to naive timestamp, but in certain timezone
...DateTimeIndex timezone aware, but how can you do the opposite: how can you convert a timezone aware Timestamp to a naive one, while preserving its timezone?
...
How to obtain a Thread id in Python?
...id on Linux:
import ctypes
libc = ctypes.cdll.LoadLibrary('libc.so.6')
# System dependent, see e.g. /usr/include/x86_64-linux-gnu/asm/unistd_64.h
SYS_gettid = 186
def getThreadId():
"""Returns OS thread id - Specific to Linux"""
return libc.syscall(SYS_gettid)
...
Getting the exception value in Python
...
If you don't know the type/origin of the error, you can try:
import sys
try:
doSomethingWrongHere()
except:
print('Error: {}'.format(sys.exc_info()[0]))
But be aware, you'll get pep8 warning:
[W] PEP 8 (E722): do not use bare except
...