Definition and traversal of arrays

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Common functions
Generate random numbers
echo rand (1,10);//range between 1-10

Date-time functions
Var_dump (Time ());//Unix timestamp of the current time, is a string of numbers

Date ("Y-m-d h:i:s", Time ());//Format date timestamp
Date ("y-m-d h:i:s D");//Omit time (), get a default value for current times, D English display week

Array
Arrays in C # are contiguous
1. No set concept,
Features: can store any type of data, can be discontinuous, can be indexed, or can be associated;

Defining arrays
Define array Mode one
$attr =array (All-in-one);//define a simple indexed array

Define array mode two
$attr []=1;
$attr []=2;

Var_dump ($ATTR);

Define array mode three

$attr = Array ("One" = "Hello",
"=>100",
"Three" =>10.9);
Var_dump ($ATTR);

Defining an associative array

$attr = Array (
"Hello",
"2" = "222",
"World"
);
Var_dump ($ATTR);
View index value, empty auto-Add, decimal as String if key=0, the first value is overwritten,
Index is not duplicated

Array values
$attr =array (
"Hello",
"World",
100,
10.3
);
Echo $attr [0];//based on index value
Echo $attr ["Three"];//value values based on key

Iterating through an array
1.for loops for indexed arrays, unable to use connection arrays

for ($i =0; $i <count ($attr); $i + +)
{
echo $attr [$i]. " <br> ";
}
Stitching up

2.foreach traversal, suitable for all arrays
foreach ($attr as $v)
{
echo $v. " <br> ";

}
foreach ($attr as $k = + $v)//second form
{
echo $k. " --". $v." <br> ";
or echo "{$k}--{$v}<br>"
}

3. Use each () and list () to combine traversal
Var_dump (each ($attr));//returns details on the current element inside the array
Var_dump (each ($attr));
Var_dump (each ($attr));

A special kind of
$attr =array;//assigns each element in the right array to the list () argument
The right array must contain an index
List ($a, $b, $c) = $attr;
echo $a;
Echo $b;
Echo $c;

while (list ($k, $v) =each ($attr));//assignment statement, execution failure returns a Falue

{
echo "{$k}--{$v}<br>";
}

4. Pointer traversal
$attr =array (

"One" = "AAAA",
"Both" and "bbbb",
"Three" = "CCCC"
);
Echo current ($attr);//Take the value of the present element

echo Key ($attr);//Take the key of the current element

Next ($attr);//Move the pointer inside the array down
Prev ($attr);//move the pointer up
End ($attr);//Pointing the pointer to the last
Reset ($attr);//Pointing the pointer to the first one, resetting
Echo current ($attr);

Use it together to iterate over all the elements.
Do
{
Echo current ($attr). " <br> "
}
while (Next ($attr));
Using the Do...while loop

Definition and traversal of arrays