scanf string How to use string functions in PHP

There are many string manipulation functions in PHP. The important ones are as follows:
(1)echo, print, printf, sprintf
The first two functions are to output strings. If there is a variable name in the string, it will be replaced with Its value.
The last two functions are similar to the C functions of the same name.
(2)strchr,strlen,strtok,strrchr,strrev,strstr,strtolower,
strtoupper,substr,ucfirst
These are commonly used string manipulation functions, some It has the same meaning as the function of the same name in C.
strrev is to flip a string.
The meaning of strtolower and strtoupper should not need to be explained.
ucfirst is to turn the first character of the string into uppercase.
substr is the return character A substring of a string, the usage is: substr (string, head, length).
The head position is calculated from 0. If it is a negative number, it means counting forward from the tail.
(3)Chr,Ord
Similar to the C function of the same name.
(4)explode,implode,join
These are functions related to arrays.
explode(string, separator) returns an array generated by dividing the string at the separator.
implode(array, separator) returns a string formed by inserting a separator between each element of the array.
join has the same meaning as implode.
(5)Chop
Remove the whitespace at the end of the string.
(6) htmlspecialchars
Replace the HTML special characters in the string with their names, for example, "<" becomes "<".
(7)nl2br
Add "(8)AddSlashes,StripSlashes
Add and remove "\" to the characters that need to be added to the string to be used for database query.
(9)parse_str
Change "name1=value1&name2=value2& ..." type string is analyzed into some variables.
For example:
parse_str("a=1&b=2");
Generate two variables $a and $b, with values ​​​​1 and 2 respectively.
If there are two If the name part of a pair of names/values ​​is the same, the value of the latter one will overwrite the previous one.
If the names of these two pairs have "[]" at the end, such as "a[]=1&a[]=2", an array will be generated $a, the two elements are 1, 2 respectively

The above introduces the scanf string and how to use the string function in PHP, including the content of scanf string. I hope it will be helpful to friends who are interested in PHP tutorials.