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Summarizing multiple columns with dplyr? [duplicate]
...brary(dplyr)
library(purrrlyr)
library(data.table)
library(bench)
set.seed(123)
n <- 10000
df <- data.frame(
a = sample(1:5, n, replace = TRUE),
b = sample(1:5, n, replace = TRUE),
c = sample(1:5, n, replace = TRUE),
d = sample(1:5, n, replace = TRUE),
grp = sample(1:3, n, replac...
Retrieving parameters from a URL
...
import urlparse
url = 'http://example.com/?q=abc&p=123'
par = urlparse.parse_qs(urlparse.urlparse(url).query)
print par['q'][0], par['p'][0]
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C++ protobuf使用入门实例 - C/C++ - 清泛网 - 专注C/C++及内核技术
...ze------
google::protobuf::TestValue msg_val;
msg_val.set_number_value(123.f);
std::string str = msg_val.SerializeAsString();
std::cout << "--------- len:" << str.length() << ":" << str << std::endl;
google::protobuf::Test message;
message.mutable_fields()->operator []("test") = msg_va...
Map vs Object in JavaScript
...d Symbol keys where as Maps support more or less any key type.
If I do obj[123] = true and then Object.keys(obj) then I will get ["123"] rather than [123]. A Map would preserve the type of the key and return [123] which is great. Maps also allow you to use Objects as keys. Traditionally to do this y...
Write a number with two decimal places SQL server
...ters to display, and the number of decimal places to display
Select Str(12345.6789, 12, 3)
displays: ' 12345.679' ( 3 spaces, 5 digits 12345, a decimal point, and three decimal digits (679). - it rounds if it has to truncate, (unless the integer part is too large for the total size, in whic...
How to format numbers as currency string?
... id="x"&gt;(press button to get output)&lt;/p&gt;
Use it like so:
(123456789.12345).formatMoney(2, ".", ",");
If you're always going to use '.' and ',', you can leave them off your method call, and the method will default them for you.
(123456789.12345).formatMoney(2);
If your culture h...
Jackson JSON custom serialization for certain fields
...ill result in the desired output
{"name":"Joe","age":25,"favoriteNumber":"123"}
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How to create a new database using SQLAlchemy?
...
123
SQLAlchemy-Utils provides custom data types and various utility functions for SQLAlchemy. You ...
How to show full object in Chrome console?
...null,4));
}
// how to call it
let obj = { a: 1, b: [2,3] };
print('hello',123,obj);
will output in console:
[
"hello",
123,
{
"a": 1,
"b": [
2,
3
]
}
]
sha...
Why does Javascript's regex.exec() not always return the same value? [duplicate]
...ignment as the loop condition.
var re = /foo_(\d+)/g,
str = "text foo_123 more text foo_456 foo_789 end text",
match,
results = [];
while (match = re.exec(str))
results.push(+match[1]);
DEMO: http://jsfiddle.net/pPW8Y/
If you don't like the placement of the assignment, the loo...