➤ In this note we will look at some commonly used functions to manipulate strings. •

strlen()

// function returns the length of a string.
echo strlen("Hello"); // outputs 5

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str_word_count()

// function counts the number of words in a string.
echo str_word_count("Hello world!"); // outputs 2

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strrev()

// function reverses a string.
echo strrev("Levani"); // outputs inaveL

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strpos()

/* function searches for a specific text within a string. 
If a match is found, the function returns the character position of 
the first match. If no match is found, it will return FALSE.*/
echo strpos("Hello world!", "l"); // outputs 2 
// why ?     index 0 = "H", index 1 = "e" and index 2 = "l"

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str_replace()

// function replaces some characters with some other characters in a string.
echo str_replace("l", "L", "levani"); // outputs Levani

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substr()

// function return part of a string between given indexes
echo substr("Hello world", 6)."\n"; // outputs world
echo substr("Hello world", 9, 2)."\n"; // outputs ld
echo substr("abcdef", -1)."\n";    // outputs f
echo substr("abcdef", -2)."\n";    // outputs ef
echo substr("abcdef", -3, 1)."\n"; // outputs d

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strtoupper()

// function  make a string uppercase
echo strtoupper("i love coding")."\n"; // outputs I LOVE CODING

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strtolower()

// function make a string lowercase
echo strtolower("PHP")."\n"; // outputs php

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explode()

// function Split a string by a string
echo var_dump(explode(" ", "I am 19 years old"))."\n"; // outputs "I" "am" "19" ...

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implode()

// function  join array elements with a string
echo implode(" ", ['Nika', 'Giorgi',"Saba"]); // outputs Nika Giorgi Saba

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trim()

// function strip whitespace (or other characters) from the beginning and end of a string
echo trim("              How are you ?     ")."\n";
// outputs How are you ? (without any whitespace before and after the text)