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What happens when a duplicate key is put into a HashMap?
...e times to HashMap ’s put method, what happens to the original value? And what if even the value repeats? I didn’t find any documentation on this.
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Python: List vs Dict for look up table
...f you don't need to associate values, use sets.
Memory
Both dictionaries and sets use hashing and they use much more memory than only for object storage. According to A.M. Kuchling in Beautiful Code, the implementation tries to keep the hash 2/3 full, so you might waste quite some memory.
If you...
Are PDO prepared statements sufficient to prevent SQL injection?
...erver's expecting on the connection both to encode ' as in ASCII i.e. 0x27 and to have some character whose final byte is an ASCII \ i.e. 0x5c. As it turns out, there are 5 such encodings supported in MySQL 5.6 by default: big5, cp932, gb2312, gbk and sjis. We'll select gbk here.
Now, it's very i...
Modulo operation with negative numbers
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Should the compiler be smart enough and detect that an unsigned modulo another unsigned is always positive? Currently (well, GCC 5.2) the compiler seems to think that "%" returns an "int" in this case, rather than "unsigned" even when both operands are uint32_...
How can I quantify difference between two images?
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General idea
Option 1: Load both images as arrays (scipy.misc.imread) and calculate an element-wise (pixel-by-pixel) difference. Calculate the norm of the difference.
Option 2: Load both images. Calculate some feature vector for each of them (like a histogram). Calculate distance between featu...
Possible reason for NGINX 499 error codes
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Its happens on my Angular APP if the user closes the tab and my API requests does not get completed.
– Vivek Saurabh
Jun 26 at 7:20
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What are the Android SDK build-tools, platform-tools and tools? And which version should be used?
...imentary question, but to my surprise, I could not find any document about Android SDK Build-tools.
Besides Android SDK Tools and Android SDK Platform-tools, there are a bunch of Android SDK Build-tools as shown in the appended screenshot. Could anyone point to a source explaining all of them and he...
Is there a REAL performance difference between INT and VARCHAR primary keys?
...AR as the primary key for reference lists (think US States, Country Codes) and a coworker won't budge on the INT AUTO_INCREMENT as a primary key for all tables.
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How to use Regular Expressions (Regex) in Microsoft Excel both in-cell and loops
How can I use regular expressions in Excel and take advantage of Excel's powerful grid-like setup for data manipulation?
9 ...
How do I clone a subdirectory only of a Git repository?
...it.
Implementing something like this in Git would be a substantial effort and it would mean that the integrity of the clientside repository could no longer be guaranteed. If you are interested, search for discussions on "sparse clone" and "sparse fetch" on the git mailinglist.
In general, the cons...