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PostgreSQL: Difference between text and varchar (character varying)
...d, and there is no overhead to store the length.
I just made a table of 1,000,000 random "char" chosen from the lower-case alphabet. A query to get a frequency distribution (select count(*), field ... group by field) takes about 650 milliseconds, vs about 760 on the same data using a text field.
...
Why does overflow:hidden not work in a ?
...rflow: hidden;
white-space: nowrap;
width: 100px;
border: solid 1px #000;
}
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This_is_a_terrible_example_of_thinking_outside_the_box.
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This_is_a_terribl...
MySQL: Large VARCHAR vs. TEXT?
... message text as either VARCHAR or TEXT. I'm setting a front-end limit of 3000 characters which means the messages would never be inserted into the db as longer than this.
...
How do I increase the capacity of the Eclipse output console?
...cters) to something much bigger. 2147383647 / ~2GB is the upper limit (or 1000000 / ~1MB in older releases). Or just uncheck the Limit console output.
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Accessing dict_keys element by index in Python3
... dicts, since the whole thing doesn't have to be stored in memory.
For 10.000.000 items I found it to be almost 40.000 times faster.
*The first item in case of a dict being just a pseudo-random item before Python 3.6 (after that it's ordered in the standard implementation, although it's not advise...
Pandas percentage of total with groupby
...d': list(range(1, 7)) * 2,
'sales': [np.random.randint(100000, 999999)
for _ in range(12)]})
state_office = df.groupby(['state', 'office_id']).agg({'sales': 'sum'})
# Change: groupby state_office and divide by sum
state_pcts = state_office.groupby(leve...
How to show popup message like in Stack Overflow
...i).fadeIn("fast");
setTimeout(i, (f ? Math.max(2500, h.length * 40) : 1000 * 30))
}
css
.error-notification{z-index:1;cursor:pointer;display:none;position:absolute;padding:15px;-moz-box-shadow:2px 2px 5px #000;-webkit-box-shadow:2px 2px 5px #000;box-shadow:2px 2px 5px #000;}
.error-notificati...
DateTime2 vs DateTime in SQL Server
... specific instant in time, not a time zone.
– Suncat2000
Jun 1 '17 at 12:51
6
@Porad: What exactl...
How to convert ASCII code (0-255) to its corresponding character?
...g.valueOf(Character.toChars(i)). Running a quick benchmark of converting 1,000,000 random integers in the given range (100 times, to be safe) on my machine gives an average time of 153.07 nanoseconds vs. 862.39 nanoseconds. However, in any interesting application, there will be far more important th...
MFC CString::Format()函数详解 - C/C++ - 清泛网 - 专注C/C++及内核技术
...浮点数，
Format("this is %e",-2.22);
返回的是：this is -2.220000E+000
等一下再说明如果将数的精度缩小
g 这个只能对应浮点型，且它会将值中多余的数去掉
Format("this is %g",02.200);
返回的是：this is 2.2
n 只能对应浮点型，...