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Swapping column values in MySQL
...-+
3 rows in set (0.00 sec)
mysql> update swapper set
-> foo = concat(foo, "###", bar),
-> bar = replace(foo, concat("###", bar), ""),
-> foo = replace(foo, concat(bar, "###"), "");
Query OK, 3 rows affected (0.00 sec)
Rows matched: 3 Changed: 3 Warnings: 0
mysql> se...
Add new row to dataframe, at specific row-index, not appended?
... 5 50 500 5000 50000 5e+05
insertRow2(existingDF, newrow, r) 549861.5 579579.0 789452 2512926 46994560 414790214
insertRow(existingDF, newrow, r) 895401.0 905318.5 1168201 2603926 39765358 392...
Rails 4 LIKE query - ActiveRecord adds quotes
...xpose you to SQL-injection (which is bad). I would suggest you use the SQL CONCAT() function to prepare the string like so:
"name LIKE CONCAT('%',?,'%') OR postal_code LIKE CONCAT('%',?,'%')", search, search)
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How to write to an existing excel file without overwriting data (using pandas)?
...iteration you append the dataframe to a list. In the end you only need to concat. If they follow the same structure will work as a charm. list_my_dfs = [df1, df2, ...] # List of your dataframes my_dfs_together = pd.concat(list_my_df ) # concat my dataframes in a single df
– ...
Add one row to pandas DataFrame
... It is worth noting however, that concat (and therefore append) makes a full copy of the data, and that constantly reusing this function can create a significant performance hit. If you need to use the operation over several datasets, use a list comprehension...
Detect if value is number in MySQL
...
This should work in most cases.
SELECT * FROM myTable WHERE concat('',col1 * 1) = col1
It doesn't work for non-standard numbers like
1e4
1.2e5
123. (trailing decimal)
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im...
JavaScript curry: what are the practical applications?
...guments);
return function() {
return __method.apply(this, args.concat([].slice.apply(null, arguments)));
}
}
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...
Portable way to get file size (in bytes) in shell?
...ays in my opinion with common Linux tools are:
$ stat -c %s /usr/bin/stat
50000
$ wc -c < /usr/bin/wc
36912
But I just don't want to be typing parameters or pipe the output just to get a file size, so I'm using my own bfsize.
...
Split array into chunks
...', {
value: function(chunkSize) {
var array = this;
return [].concat.apply([],
array.map(function(elem, i) {
return i % chunkSize ? [] : [array.slice(i, i + chunkSize)];
})
);
}
});
console.log(
[1, 2, 3, 4, 5, 6, 7].chunk_inefficient(3)
)
// [[1,...
How do you install an APK file in the Android emulator?
... people are by luck getting adb in their paths.
– Hal50000
May 1 '16 at 14:30
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