大约有 40,000 项符合查询结果(耗时:0.0566秒) [XML]
Add Foreign Key to existing table
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To add a foreign key (grade_id) to an existing table (users), follow the following steps:
ALTER TABLE users ADD grade_id SMALLINT UNSIGNED NOT NULL DEFAULT 0;
ALTER TABLE users ADD CONSTRAINT fk_grade_id FOREIGN KEY (grade_id) REFERENCES grades(id);
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Finding sum of elements in Swift array
...st) way to find the sum of an array of integers in swift?
I have an array called multiples and I would like to know the sum of the multiples.
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Get last n lines of a file, similar to tail
... blocks.append(f.read(BLOCK_SIZE))
else:
# file too small, start from begining
f.seek(0,0)
# only read what was not read
blocks.append(f.read(block_end_byte))
lines_found = blocks[-1].count('\n')
lines_to_go -= lines_found
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how do I make a single legend for many subplots with matplotlib?
... multiple subplots with matplotlib. That is, I have 9 plots on a 3x3 grid, all with the same for lines (of course, different values per line).
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How to query SOLR for empty fields?
...ou need to change QueryParameter.cs (Create a new parameter)
private bool _negativeQuery = false;
public QueryParameter(string field, string value, ParameterJoin parameterJoin = ParameterJoin.AND, bool negativeQuery = false)
{
this._field = field;
this._value = value.Trim();
this._para...
Is “inline” without “static” or “extern” ever useful in C99?
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Actually this excellent answer also answers your question, I think:
What does extern inline do?
The idea is that "inline" can be used in a header file, and then "extern inline" in a .c file. "extern inline" is just how you ins...
How to set a value of a variable inside a template code?
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If you need to declare a list, use make_list. docs.djangoproject.com/en/1.9/ref/templates/builtins/#make-list
– MrValdez
Jul 1 '16 at 7:55
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in_array() and multidimensional array
...sive (hence the _r, analogous to print_r(), for example). It descends into all nested arrays to search for the value until there are no more arrays to be found. This way, you can search through arrays of arbitrary complexity instead of just two levels deep.
– jwueller
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How to read json file into java with simple JSON library
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Well, you want to process all of the items in the array in a loop. My code just gets you the first item (a.get(0)) because that was the closest match to your original code. The json-simple documentation says a JSONArray is java.util.List, so you can...
Why use Ruby's attr_accessor, attr_reader and attr_writer?
...write classes which will work correctly no matter how their public API is called.
class Person
attr_accessor :age
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end
Here, I can see that I may both read and write the age.
class Person
attr_reader :age
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end
Here, I can see that I may only read the age. Imagine that it is set ...