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Check if a given key already exists in a dictionary
...()
for i in range(100):
key = i % 10
d[key] = d.get(key, 0) + 1
and if you wanted to always ensure a default value for any key you can either use dict.setdefault() repeatedly or defaultdict from the collections module, like so:
from collections import defaultdict
d = defaultdict(int)
f...
How to update Ruby to 1.9.x on Mac?
I have created a new user account on my mac and I am trying to update to the current version of ruby on it (1.9.2) from the snow leopard default of 1.8.7. Can somebody point me to tutorial or explain the best method to update Ruby on my mac from 1.8 to 1.9.2? Thanks
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Vagrant error: NFS is reporting that your exports file is invalid
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Try using the known good versions of VirtualBox and Vagrant noted in Discourse as Your First Rails App:
Vagrant 1.1.2
VirtualBox 4.2.10
I was having the same issue on Mac (OS X 10.9 (Mavericks)), but rolling back to these versions seemed to fix it for me.
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What is the difference between char s[] and char *s?
...o world";
will place "Hello world" in the read-only parts of the memory, and making s a pointer to that makes any writing operation on this memory illegal.
While doing:
char s[] = "Hello world";
puts the literal string in read-only memory and copies the string to newly allocated memory on the...
max value of integer
In C, the integer (for 32 bit machine) is 32 bits, and it ranges from -32,768 to +32,767.
In Java, the integer(long) is also 32 bits, but ranges from -2,147,483,648 to +2,147,483,647.
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How to output a multiline string in Bash?
... -d '' help <<- EOF ... to read the multiline string into a variable and then echoed the result.
– helpermethod
Jun 10 '12 at 21:11
3
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Remove the last line from a file in Bash
...sed.
MacOS:
On Mac OS X (as of 10.7.4), the equivalent of the sed -i command above is
sed -i '' -e '$ d' foo.txt
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std::string to float or double
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The Standard Library (C++11) offers the desired functionality with std::stod :
std::string s = "0.6"
std::wstring ws = "0.7"
double d = std::stod(s);
double dw = std::stod(ws);
Generally for most other basic types, see <st...
When should I use Struct vs. OpenStruct?
In general, what are the advantages and disadvantages of using an OpenStruct as compared to a Struct? What type of general use-cases would fit each of these?
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How to do Base64 encoding in node.js?
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Buffers can be used for taking a string or piece of data and doing base64 encoding of the result. For example:
> console.log(Buffer.from("Hello World").toString('base64'));
SGVsbG8gV29ybGQ=
> console.log(Buffer.from("SGVsbG8gV29ybGQ=", 'base64').toString('ascii'))
Hello Worl...