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const char * const versus const char *?
I'm running through some example programs to refamiliarize myself with C++ and I have run into the following question. First, here is the example code:
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Defining custom attrs
I need to implement my own attributes like in com.android.R.attr
5 Answers
5
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Using context in a fragment
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I was reading this Google blog on memory leaks...android-developers.blogspot.com/2009/01/… . If I use the getActivity() method would the app not be at risk of memory leaks? The blog suggests "Try using the context-application instead of a context-activity" which isn't rea...
Possible heap pollution via varargs parameter
I understand this occurs with Java 7 when using varargs with a generic type;
5 Answers
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Numpy how to iterate over columns of array?
Suppose I have and m x n array. I want to pass each column of this array to a function to perform some operation on the entire column. How do I iterate over the columns of the array?
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Extract subset of key-value pairs from Python dictionary object?
...bigdict.get(k, None) for k in ('l', 'm', 'n')}
If you're using Python 3, and you only want keys in the new dict that actually exist in the original one, you can use the fact to view objects implement some set operations:
{k: bigdict[k] for k in bigdict.keys() & {'l', 'm', 'n'}}
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Generate random int value from 3 to 6
Is it possible in Microsoft SQL Server generate random int value from Min to Max (3-9 example, 15-99 e.t.c)
10 Answers
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How do I move a single folder from one Subversion repository to another repository?
...t repository, filter it to only include information about the docs folder, and load it into the other repository.
Would be something like this:
svnadmin dump /svn/old_repos > ./repository.dump
svndumpfilter include path/to/docs --drop-empty-revs --renumber-revs --preserve-revprops < ./reposi...
Find rows that have the same value on a column in MySQL
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This query will give you a list of email addresses and how many times they're used, with the most used addresses first.
SELECT email,
count(*) AS c
FROM TABLE
GROUP BY email
HAVING c > 1
ORDER BY c DESC
If you want the full rows:
select * from table where email ...
Extract a substring according to a pattern
...we create a data frame with two columns, one for the part before the colon and one for after, and then extract the latter.
library(dplyr)
library(tidyr)
library(purrr)
DF <- data.frame(string)
DF %>%
separate(string, into = c("pre", "post")) %>%
pull("post")
## [1] "E001" "E002" "E00...