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Count table rows
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Is it any faster when I use name of indexed column instead of * ? Like this: SELECT COUNT(id) FROM tablename
– user1810543
Nov 8 '12 at 21:01
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“INSERT IGNORE” vs “INSERT … ON DUPLICATE KEY UPDATE”
...ou're looking for as well. As long as you know that rows which would cause index conflicts will not be inserted and you plan your program accordingly, it shouldn't cause any trouble.
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MongoDB Aggregation: How to get total records count?
... { $group: { _id: null, count: { $sum: 1 } } }
] ).map(function(record, index){
print(index);
});
The aggregate will return the array so just loop it and get the final index .
And other way of doing it is:
var count = 0 ;
db.collection.aggregate([
{ $match : { score : { $gt : 70, $lt...
In PHP what does it mean by a function being binary-safe?
...ing is more specific, referring only to what Michael gives as an example.
All strings in PHP have a length associated, which are the number of bytes that compose it. When a function manipulates a string, it can either:
Rely on that length meta-data.
Rely on the string being null-terminated, i.e.,...
How do I use PHP to get the current year?
... for the year to be out-of-date. How would I make the year update automatically with PHP 4 and PHP 5 ?
25 Answers
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How to apply a function to two columns of Pandas dataframe
...unction f, rewrite the function to accept a pandas Series object, and then index the Series to get the values needed.
In [49]: df
Out[49]:
0 1
0 1.000000 0.000000
1 -0.494375 0.570994
2 1.000000 0.000000
3 1.876360 -0.229738
4 1.000000 0.000000
In [50]: def f(x):
...
What's better at freeing memory with PHP: unset() or $var = null
I realise the second one avoids the overhead of a function call ( update , is actually a language construct), but it would be interesting to know if one is better than the other. I have been using unset() for most of my coding, but I've recently looked through a few respectable classes found off t...
When to use enumerateObjectsUsingBlock vs. for
...ons:
for (id x in y){
}
[y enumerateObjectsUsingBlock:^(id x, NSUInteger index, BOOL *stop){
}];
Even if you add a variable to track the index, the simple loop is easier to read.
So when you should use enumerateObjectsUsingBlock:? When you're storing a block to execute later or in multiple plac...
Alternate FizzBuzz Questions [closed]
...2th term, F12, is the first term to contain three digits.
What is the index of the first term in the Fibonacci sequence to
contain 1000 digits?
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Why does Python use 'magic methods'?
...e FAQ:
Why does Python use methods for some
functionality (e.g. list.index()) but
functions for other (e.g. len(list))?
The major reason is history. Functions
were used for those operations that
were generic for a group of types and
which were intended to work even for
objects t...