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Why is Multiple Inheritance not allowed in Java or C#?
...omplexity to the languages while providing too little benefit.
For a more fun and in-depth read, there are some articles available on the web with interviews of some of the language designers. For example, for .NET, Chris Brumme (who worked at MS on the CLR) has explained the reasons why they decid...
Writing Unicode text to a text file?
...eError: # Python 3
unicode_chr = chr
exclude_categories = set(('Co', 'Cn'))
counts = Counter()
control_names = dict(enumerate(controlnames))
with io.open('unidata', 'w', encoding='utf-8') as f:
for x in range((2**8)**3):
try:
char = unicode_chr(x)
except ValueEr...
Which is faster in Python: x**.5 or math.sqrt(x)?
... (Python 2.5.2, Windows):
$ python -mtimeit -s"from math import sqrt; x = 123" "x**.5"
1000000 loops, best of 3: 0.445 usec per loop
$ python -mtimeit -s"from math import sqrt; x = 123" "sqrt(x)"
1000000 loops, best of 3: 0.574 usec per loop
$ python -mtimeit -s"import math; x = 123" "math.sqrt(x...
How to represent multiple conditions in a shell if statement?
...
Classic technique (escape metacharacters):
if [ \( "$g" -eq 1 -a "$c" = "123" \) -o \( "$g" -eq 2 -a "$c" = "456" \) ]
then echo abc
else echo efg
fi
I've enclosed the references to $g in double quotes; that's good practice, in general. Strictly, the parentheses aren't needed because the preced...
php中json_decode()和json_encode()的使用方法 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...d"] => int(4)
["e"] => int(5)
}
$data='[
{"Name":"a1","Number":"123","Contno":"000","QQNo":""},
{"Name":"a1","Number":"123","Contno":"000","QQNo":""},
{"Name":"a1","Number":"123","Contno":"000","QQNo":""}
]';
echo json_decode($data);
结果为：
Array ( [0] => stdClass Object ( ...
Kotlin Ternary Conditional Operator
...
You could define your own Boolean extension function that returns null when the Boolean is false to provide a structure similar to the ternary operator:
infix fun <T> Boolean.then(param: T): T? = if (this) param else null
This would make an a ? b : c expressio...
How do I split a string, breaking at a particular character?
...h JavaScript’s String.prototype.split function:
var input = 'john smith~123 Street~Apt 4~New York~NY~12345';
var fields = input.split('~');
var name = fields[0];
var street = fields[1];
// etc.
share
|
...
Reading binary file and looping over each byte
... example uses a chunksize of 8192 Bytes. The parameter for the file.read()-function simply specifies the size, i.e. the number of Bytes to be read. codeape chose 8192 Byte = 8 kB (actually it's KiB but that's not as commonly known). The value is "totally" random but 8 kB seems to be an appropriate v...
Can functions be passed as parameters?
...ing.
func value(x int) string {
return fmt.Sprintf("%v", x)
}
// quote123 passes 123 to convert func and returns quoted string.
func quote123(fn convert) string {
return fmt.Sprintf("%q", fn(123))
}
func main() {
var result string
result = value(123)
fmt.Println(result)
//...
How to display pandas DataFrame of floats using a format string for columns?
... pd
pd.options.display.float_format = '${:,.2f}'.format
df = pd.DataFrame([123.4567, 234.5678, 345.6789, 456.7890],
index=['foo','bar','baz','quux'],
columns=['cost'])
print(df)
yields
cost
foo $123.46
bar $234.57
baz $345.68
quux $456.79
but this ...