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Read text file into string array (and write)
The ability to read (and write) a text file into and out of a string array is I believe a fairly common requirement. It is also quite useful when starting with a language removing the need initially to access a database. Does one exist in Golang?
e.g.
...
Read and overwrite a file in Python
... race conditions, you could truncate it:
f = open(filename, 'r+')
text = f.read()
text = re.sub('foobar', 'bar', text)
f.seek(0)
f.write(text)
f.truncate()
f.close()
The functionality will likely also be cleaner and safer using open as a context manager, which will close the file handler, even if a...
Docker, mount volumes as readonly
...r each execution, which would be too costly), but I want that folder to be read-only. Changing the folder owner to someone else works. However, chown requires root access, which I would prefer not to expose to an application.
...
What is the difference between atomic / volatile / synchronized?
...;
public int getNextUniqueIndex() {
return counter++;
}
It basically reads value from memory, increments it and puts back to memory. This works in single thread but nowadays, in the era of multi-core, multi-CPU, multi-level caches it won't work correctly. First of all it introduces race condit...
What is a stream?
...ich can be accessed in sequential order. Typical operations on a stream:
read one byte. Next time you read, you'll get the next byte, and so on.
read several bytes from the stream into an array
seek (move your current position in the stream, so that next time you read you get bytes from the new po...
How to read a large file - line by line?
...want to iterate over each line of an entire file. One way to do this is by reading the entire file, saving it to a list, then going over the line of interest. This method uses a lot of memory, so I am looking for an alternative.
...
Why do enum permissions often have 0, 1, 2, 4 values?
...e they are powers of two and I can do this:
var permissions = Permissions.Read | Permissions.Write;
And perhaps later...
if( (permissions & Permissions.Write) == Permissions.Write )
{
// we have write access
}
It is a bit field, where each set bit corresponds to some permission (or wha...
Using R to download zipped data file, extract, and import data
...download.file("http://www.newcl.org/data/zipfiles/a1.zip",temp)
data <- read.table(unz(temp, "a1.dat"))
unlink(temp)
Compressed (.z) or gzipped (.gz) or bzip2ed (.bz2) files are just the file and those you can read directly from a connection. So get the data provider to use that instead :)
...
Get MD5 hash of big files in Python
...ct that MD5 has 128-byte digest blocks (8192 is 128×64). Since you're not reading the entire file into memory, this won't use much more than 8192 bytes of memory.
In Python 3.8+ you can do
import hashlib
with open("your_filename.txt", "rb") as f:
file_hash = hashlib.md5()
while chunk := f...
How to get JSON from webpage into Python script
...m/maps/api/geocode/json?address=google") as url:
data = json.loads(url.read().decode())
print(data)
Python2 example:
import urllib, json
url = "http://maps.googleapis.com/maps/api/geocode/json?address=google"
response = urllib.urlopen(url)
data = json.loads(response.read())
print data
T...