Learn PHP is no longer difficult to master the following commonly used functions

One, write the file
1. Open resource (file) fopen ($filename, $mode)
2. Write file fwrite ($handle, $STR)
3. Close file fclose ($handle)
4. One-step write File_put_contents ($filename, $str, $mode) file_append lock_ex
}

Second, read the document
1. Read file Fread ($handle, number of bytes)
2. Read a line of fgets ($handle);
3. Read a character fgetc ($handle)
4. Read into an array of file ($filename)
5. One-step read file_get_contents ($filename)

Third, directory operations
1, Build catalog mkdir ($dirname)
2. Delete directory RmDir ($dirname)
3, Open Directory handle Opendir ($dirname)
4, read the number of catalog strips Readdir ($handle)
5, Close directory resource Closedir ($handle)
6, Reset directory resource Rewinddir ($dirname);

Iv. directory and file operations
1. Check if the file or directory exists file_exists ($filename)
2, file or directory rename rename ($file)

v. operation of files
1 copy file copy (' original file ', ' target file ')
2 Deleting Files unlink ($filename)
3 Get File size filesize ($filename)
4 acquisition of file creation time Filectime ($filename)
5 Access time for Files Fileatime ($filename)
6 time to get the file modified Filemtime ($filename)

Vi. Path Operation1 Get Path DirName ($path)
2 Get filename basename ($path)
3 Getting path information PathInfo ($path)

Vii. Array functions (extremely important)

What this post hides 1. Inserts an element at the beginning of the array array_unshift ($arr, $v)
2. Add array elements at the end of the array Array_push ($arr, $v, $v 1 ...)
3. Move the first element of the array out and return this element Array_shift ($arr)
4. Delete element Array_pop ($arr) at the tail of the array
5. Concatenate the array with $separator into a string implode ($a, $arr)
6. Detect if the variable is an array Is_array ($arr)
7. Get the array's key name Array_keys ($arr)
8. Get the value of the array array_values ($arr)
9. Retrieves whether $value is in $arr, returns a Boolean value In_array ($v, $arr)
10. Retrieves the array $arr, whether there is $key this key name Array_key_exists ($k, $arr)
11. Retrieves whether the $value is in $arr, if there is a return key name Array_search ($value, $arr)
12. Reverse an array and, if the second argument is true, keep the key name Array_reverse ($arr, True)
13. Exchanging the keys and values of an array array_flip ($arr)
14. Count the number of array elements ($arr)
15. Count occurrences of all values in the array array_count_values ($arr)
16. Remove duplicate values from the Array_unique ($arr)
17. Values from small to large sorted sort ($arr)
18. Values from large to small sort rsort ($arr)
19. Key from small to large sort ksort ($arr)
20. Key from large to small sort krsort ($arr)
21. Randomly get $num elements from an array array_rand ($arr, $num)
22. Sum all elements of an array array_sum ($arr)
23. Merging Arrays Array_merge ($arr, $arr)
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Eight, String functions (extremely important)

What's hidden in this post

1. Output string echo ($STR) echo
2. Output as-is (distinguish between single and double quotation marks) print ($STR)
3. Output string, end Script execution Die ($STR):d ie ($str) die;
4. Output string, end Script execution exit ($STR) exit;
5. Output formatted string printf ($str, $p 1,...)
6. Do not output formatted string directly, return formatted string, save to variable sprintf ($str, $p 1,...)
7. Information about printing variables Var_dump ($p)
8. String conversion to lowercase strtolower ($str)
9. Convert string to uppercase Strtoupper ($STR)
10. Convert the first character of a string to uppercase Ucfirst ($STR)
11. Convert each word in a string to uppercase Ucwords ($STR)
12. Remove whitespace characters at both ends of the string. Trim ($str, ', ')
13. Remove the left white space character from the string. Ltrim ($STR)
14. Remove the whitespace character to the right of the string. Rtrim ($STR)
Whitespace characters: "", "\ T", "\ n", "\ R", "s"
15 getting the string length strlen ($str)
16 statistics contains the number of strings Substr_count ($str, ' substring ')
17 returns a substring with a length of $length in the string $string, starting with $start
Substr ($string, $start [, $length])
18 Returns a substring of string $string, $search the first occurrence to the end of the string.
Strstr ($string, $search)
19 Find the first bit of $search in $str, starting with $offset.
Strpos ($str, $search [, int $offset])
20. Find the last position of $search in $str, starting from $offset
Strrpos ($str, $search [, int $offset])
21. Replace all the $search in the $str with the $replace.
Str_replace ($search, $replace, $STR)
22. Repeat the output of the specified string
Str_repeat ()
23. Encrypt strings
MD5 ()
24. String flipping
Strrev ()
25. Use a string to split another string, forming an array//string into an array
Explode ("delimiter", $str);

Learn PHP is no longer difficult to master the following commonly used functions