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How to import multiple .csv files at once?
...olutions in other answers using things like do.call(rbind,...), dplyr::bind_rows() or data.table::rbindlist().
If you really want each data frame in a separate object, even though that's often inadvisable, you could do the following with assign:
temp = list.files(pattern="*.csv")
for (i in 1:lengt...
How to add column if not exists on PostgreSQL?
...statement:
DO $$
BEGIN
BEGIN
ALTER TABLE <table_name> ADD COLUMN <column_name> <column_type>;
EXCEPTION
WHEN duplicate_column THEN RAISE NOTICE 'column <column_name> already exists in <table_name>.';
END;
END;
$$
...
Override Python's 'in' operator?
...
MyClass.__contains__(self, item)
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“Comparison method violates its general contract!”
...ode:
public int compareTo(tfidfContainer compareTfidf) {
//descending order
if (this.tfidf > compareTfidf.tfidf)
return -1;
else if (this.tfidf < compareTfidf.tfidf)
return 1;
else
return 0;
}
The transitive property clearly holds, but for some re...
Setting up two different static directories in node.js Express framework
...nal (first) parameter to use() like so:
app.use("/public", express.static(__dirname + "/public"));
app.use("/public2", express.static(__dirname + "/public2"));
That way you get two different directories on the web that mirror your local directories, not one url path that fails over between two lo...
Differences between INDEX, PRIMARY, UNIQUE, FULLTEXT in MySQL?
...stems (such as MySQL's InnoDB) will store a table's records on disk in the order in which they appear in the PRIMARY index.
FULLTEXT indexes are different from all of the above, and their behaviour differs significantly between database systems. FULLTEXT indexes are only useful for full text searc...
Python debugging tips [closed]
...
PDB
You can use the pdb module, insert pdb.set_trace() anywhere and it will function as a breakpoint.
>>> import pdb
>>> a="a string"
>>> pdb.set_trace()
--Return--
> <stdin>(1)<module>()->None
(Pdb) p a
'a string'
(Pdb)
To...
Short circuit Array.forEach like calling break
...cause some returns true as soon as any of the callbacks, executed in array order, return true, short-circuiting the execution of the rest.
some, its inverse every (which will stop on a return false), and forEach are all ECMAScript Fifth Edition methods which will need to be added to the Array.proto...
How can I get the max (or min) value in a vector?
...1, 2, 3, -1, -2, -3};
If the vector is sorted in ascending or descending order then you can find it with complexity O(1).
For a vector of ascending order the first element is the smallest element, you can get it by v[0] (0 based indexing) and last element is the largest element, you can get it b...
cpuid汇编指令 - C/C++ - 清泛网 - 专注C/C++及内核技术
... cpuid
cmp eax, 80000004h
jb not_supported
mov di, offset CPU_name
mov eax, 80000002h
cpuid
call save_string
mov eax, 80000003h
cpuid
...