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How to append rows to an R data frame
...m:
You should use stringsAsFactors if you want the characters to not get converted to factors. Use: df = data.frame(x = numeric(), y = character(), stringsAsFactors = FALSE)
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FFmpeg: How to split video efficiently?
...est4.mkv
Which outputs...
Two commands
real 0m16.201s
user 0m1.830s
sys 0m1.301s
real 0m43.621s
user 0m4.943s
sys 0m2.908s
One command
real 0m59.410s
user 0m5.577s
sys 0m3.939s
I tested a SD & HD file, after a few runs & a little maths.
Two commands SD 0m53.94 #2 wins ...
Convert an image (selected by path) to base64 string
How do you convert an image from a path on the user's computer to a base64 string in C#?
12 Answers
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Passing variable arguments to another function that accepts a variable argument list
...hat takes a variable argument list with , ... in the signature. If you've converted the variable arguments to a va_list, you can pass the va_list to another function that only takes a va_list, but that function (or one that it calls) must have some way of knowing what's in the va_list.
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“#include” a text file in a C program as a char[]
...
You have two possibilities:
Make use of compiler/linker extensions to convert a file into a binary file, with proper symbols pointing to the begin and end of the binary data. See this answer: Include binary file with GNU ld linker script.
Convert your file into a sequence of character constants...
What does if __name__ == “__main__”: do?
... foo2.py on the command-line? Why?
# Suppose this is foo2.py.
import os, sys; sys.path.insert(0, os.path.dirname(__file__)) # needed for some interpreters
def functionA():
print("a1")
from foo2 import functionB
print("a2")
functionB()
print("a3")
def functionB():
print("b...
nullable object must have a value
... resolved my problem, i just change null able object to non null able, and convert datetime to string directly, not by datetimeobject.value.datetime.tostring()
– adnan
Dec 28 '16 at 12:41
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Convert text into number in MySQL query
Is it possible to convert text into number within MySQL query? I have a column with an identifier that consists a name and a number in the format of "name-number". The column has VARCHAR type. I want to sort the rows according the number (rows with the same name) but the column is sorted according d...
Deleting folders in python recursively
... delete a file, if it is read only. therefore, one can use -
import os, sys
import stat
def del_evenReadonly(action, name, exc):
os.chmod(name, stat.S_IWRITE)
os.remove(name)
if os.path.exists("test/qt_env"):
shutil.rmtree('test/qt_env',onerror=del_evenReadonly)
...
Java equivalent of unsigned long long?
...gs (what "wrapping integer" types are). Any size number should implicitly convert to any size ring, but rings should only convert to numbers via function or via explicit typecast to the same size number. The behavior of C, where unsigned types generally behave as algebraic rings but sometimes beha...