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Comparing two dataframes and getting the differences
...to find changes, but symmetric difference. For that, one approach might be concatenate dataframes:
>>> df = pd.concat([df1, df2])
>>> df = df.reset_index(drop=True)
group by
>>> df_gpby = df.groupby(list(df.columns))
get index of unique records
>>> idx = [...
How do you add an array to another array in Ruby and not end up with a multi-dimensional result?
... [1,2,'foo','bar'].
I'm doubtless forgetting some approaches, but you can concatenate:
a1.concat a2
a1 + a2 # creates a new array, as does a1 += a2
or prepend/append:
a1.push(*a2) # note the asterisk
a2.unshift(*a1) # note the asterisk, and that a2 is the receiver
or...
UPDATE multiple tables in MySQL using LEFT JOIN
...= t1.id
SET t1.col1 = newvalue
WHERE t2.id IS NULL
Note that for a SELECT it would be more efficient to use NOT IN / NOT EXISTS syntax:
SELECT t1.*
FROM t1
WHERE t1.id NOT IN
(
SELECT id
FROM t2
)
See the article in my blog for performance details...
Drop multiple tables in one shot in mysql
... of tables to be deleted.
Get table using the below
For sql server - SELECT CONCAT(name,',') Table_Name FROM SYS.tables;
For oralce - SELECT CONCAT(TABLE_NAME,',') FROM SYS.ALL_TABLES;
Copy and paste the table names from the result set and paste it after the DROP command.
...
Append an array to another array in JavaScript [duplicate]
...embers of arrays 2 and 3 at once.
or...
array1.push.apply(array1, array2.concat(array3));
To deal with large arrays, you can do this in batches.
for (var n = 0, to_add = array2.concat(array3); n < to_add.length; n+=300) {
array1.push.apply(array1, to_add.slice(n, n+300));
}
If you ...
Limit text length to n lines using CSS
...lor: black;
width: 250px; /* Could be anything you like. */
}
.text-concat {
position: relative;
display: inline-block;
word-wrap: break-word;
overflow: hidden;
max-height: 3.6em; /* (Number of lines you want visible) * (line-height) */
line-height: 1.2em;
text-align:just...
Cartesian product of multiple arrays in JavaScript
...aScript, no lodash, underscore or other libraries:
let f = (a, b) => [].concat(...a.map(a => b.map(b => [].concat(a, b))));
let cartesian = (a, b, ...c) => b ? cartesian(f(a, b), ...c) : a;
Update:
This is the same as above but improved to strictly follow the Airbnb JavaScript Style Gui...
How to get ALL child controls of a Windows Forms form of a specific type (Button/Textbox)?
...ar controls = control.Controls.Cast<Control>();
return controls.SelectMany(ctrl => GetAll(ctrl,type))
.Concat(controls)
.Where(c => c.GetType() == type);
}
To test it in the form load event I wanted a count of all control...
Why use String.Format? [duplicate]
Why would anyone use String.Format in C# and VB .NET as opposed to the concatenation operators ( & in VB, and + in C#)?
...
Find and Replace text in the entire table using a MySQL query
...his_text";
$replace = "replace_with_this_text";
$loop = mysql_query("
SELECT
concat('UPDATE ',table_schema,'.',table_name, ' SET ',column_name, '=replace(',column_name,', ''{$find}'', ''{$replace}'');') AS s
FROM
information_schema.columns
WHERE
table_schema = '{...