Core PHP Programming, Third Edition

12.1. Strings

For the most part, the string functions create strings from other strings or report the properties of a string.

array count_chars(string data, integer mode)string count_chars(string data, integer mode)

The count_chars function (Listing 12.1) analyzes a string by the characters present. The mode argument controls the return value as described in Table 12.1. See Figure 12.1.

Table 12.1. count_chars Modes

Mode	Description
0	Returns an array indexed by ASCII codes. Each element is set with the count for that character.
1	Returns an array indexed by ASCII codes. Only characters with positive counts appear in the array.
2	Returns an array indexed by ASCII codes. Only characters with zero counts appear in the array.
3	Returns a string containing ...