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How to write DataFrame to postgres table?
... the table
conn = engine.raw_connection()
cur = conn.cursor()
output = io.StringIO()
df.to_csv(output, sep='\t', header=False, index=False)
output.seek(0)
contents = output.getvalue()
cur.copy_from(output, 'table_name', null="") # null values become ''
conn.commit()
...
Remove carriage return in Unix
...rather than just blindly within a file (you may have them in the middle of strings for all I know). Using this test file with a CR at the end of the first line only:
$ cat infile
hello
goodbye
$ cat infile | od -c
0000000 h e l l o \r \n g o o d b y e \n
0000017
dos2un...
Why does changing the returned variable in a finally block not change the return value?
... object that s references. If s was a reference to a mutable object (which String is not) and the contents of the object were changed in the finally block, then those changes would be seen in the returned value.
The detailed rules for how all this operates can be found in Section 14.20.2 of the Java...
Write string to output stream
...InputStream and OutputStream) transfer binary data. If you want to write a string to a stream, you must first convert it to bytes, or in other words encode it. You can do that manually (as you suggest) using the String.getBytes(Charset) method, but you should avoid the String.getBytes() method, beca...
How do I set the proxy to be used by the JVM
...tps.proxyPort", getHTTPPort());
if (isUseHTTPAuth()) {
String encoded = new String(Base64.encodeBase64((getHTTPUsername() + ":" + getHTTPPassword()).getBytes()));
con.setRequestProperty("Proxy-Authorization", "Basic " + encoded);
Authenticator.setDefault(n...
Node.js throws “btoa is not defined” error
...4 you could do so using Buffer:
console.log(Buffer.from('Hello World!').toString('base64'));
Reverse (assuming the content you're decoding is a utf8 string):
console.log(Buffer.from(b64Encoded, 'base64').toString());
Note: prior to Node v4, use new Buffer rather than Buffer.from.
...
Specifically, what's dangerous about casting the result of malloc?
...f. Here's an example code fragment for discussion purposes.
main()
{
char * c = (char *)malloc(2) ;
printf("%p", c) ;
}
Suppose that the returned heap pointer is something bigger than what is representable in an int, say 0xAB00000000.
If malloc is not prototyped to return a pointer, the ...
What are the underlying data structures used for Redis?
...u asked, here is the underlying implementation of every Redis data type.
Strings are implemented using a C dynamic string library so that we don't pay (asymptotically speaking) for allocations in append operations. This way we have O(N) appends, for instance, instead of having quadratic behavior.
...
How to create a new database after initally installing oracle database 11g Express Edition?
...s Connection Name, Username, and Password.
For security, the password characters that you type appear as
asterisks.
Near the Password field is the check box Save Password. By default, it
is deselected. Oracle recommends accepting the default.
In the New/Select Database Connection ...
Create a .txt file if doesn't exist, and if it does append a new line
...
string path = @"E:\AppServ\Example.txt";
File.AppendAllLines(path, new [] { "The very first line!" });
See also File.AppendAllText(). AppendAllLines will add a newline to each line without having to put it there yourself.
...