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PHP caveats – int/float type conversion

The following code checks various scenarios in which inbuilt functions like intval, floatval, is_numeric, is_float and filter_var would result for several different types of values. Feel free to run in your local, leave comments if I can make the results more interesting with some more functions.

https://gist.github.com/harshvardhanmalpani/8dd0222e4821d0e495532abe9007fef1

Output / Results

Test Value 1: (string)true
Integer converted Value: 0
Float converted Value: 0
❌ Invalid Integer as per is_numeric
❌ Invalid Float as per is_float
❌ Invalid Integer as per filter validate
❌ Invalid Float as per filter validate
----
Test Value 2: (boolean)1
Integer converted Value: 1
Float converted Value: 1
❌ Invalid Integer as per is_numeric
❌ Invalid Float as per is_float
✅ Valid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 3: (boolean)
Integer converted Value: 0
Float converted Value: 0
❌ Invalid Integer as per is_numeric
❌ Invalid Float as per is_float
❌ Invalid Integer as per filter validate
❌ Invalid Float as per filter validate
----
Test Value 4: (string)false
Integer converted Value: 0
Float converted Value: 0
❌ Invalid Integer as per is_numeric
❌ Invalid Float as per is_float
❌ Invalid Integer as per filter validate
❌ Invalid Float as per filter validate
----
Test Value 5: (integer)0
Integer converted Value: 0
Float converted Value: 0
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
✅ Valid Integer as per filter validate
❌ Invalid Float as per filter validate
----
Test Value 6: (double)-0
Integer converted Value: 0
Float converted Value: -0
✅ Valid Integer as per is_numeric
✅ Valid Float as per is_float
✅ Valid Integer as per filter validate
❌ Invalid Float as per filter validate
----
Test Value 7: (integer)0
Integer converted Value: 0
Float converted Value: 0
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
✅ Valid Integer as per filter validate
❌ Invalid Float as per filter validate
----
Test Value 8: (string)-0
Integer converted Value: 0
Float converted Value: -0
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
✅ Valid Integer as per filter validate
❌ Invalid Float as per filter validate
----
Test Value 9: (string)+0
Integer converted Value: 0
Float converted Value: 0
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
✅ Valid Integer as per filter validate
❌ Invalid Float as per filter validate
----
Test Value 10: (string)-0.0
Integer converted Value: 0
Float converted Value: -0
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
❌ Invalid Integer as per filter validate
❌ Invalid Float as per filter validate
----
Test Value 11: (string)+0.0
Integer converted Value: 0
Float converted Value: 0
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
❌ Invalid Integer as per filter validate
❌ Invalid Float as per filter validate
----
Test Value 12: (string)0
Integer converted Value: 0
Float converted Value: 0
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
✅ Valid Integer as per filter validate
❌ Invalid Float as per filter validate
----
Test Value 13: (string)0w
Integer converted Value: 0
Float converted Value: 0
❌ Invalid Integer as per is_numeric
❌ Invalid Float as per is_float
❌ Invalid Integer as per filter validate
❌ Invalid Float as per filter validate
----
Test Value 14: (string)0.0t
Integer converted Value: 0
Float converted Value: 0
❌ Invalid Integer as per is_numeric
❌ Invalid Float as per is_float
❌ Invalid Integer as per filter validate
❌ Invalid Float as per filter validate
----
Test Value 15: (string)0.1
Integer converted Value: 0
Float converted Value: 0.1
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
❌ Invalid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 16: (double)0.1
Integer converted Value: 0
Float converted Value: 0.1
✅ Valid Integer as per is_numeric
✅ Valid Float as per is_float
❌ Invalid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 17: (integer)1
Integer converted Value: 1
Float converted Value: 1
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
✅ Valid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 18: (string)1
Integer converted Value: 1
Float converted Value: 1
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
✅ Valid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 19: (double)10000
Integer converted Value: 10000
Float converted Value: 10000
✅ Valid Integer as per is_numeric
✅ Valid Float as per is_float
✅ Valid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 20: (string)2e
Integer converted Value: 2
Float converted Value: 2
❌ Invalid Integer as per is_numeric
❌ Invalid Float as per is_float
❌ Invalid Integer as per filter validate
❌ Invalid Float as per filter validate
----
Test Value 21: (double)20000
Integer converted Value: 20000
Float converted Value: 20000
✅ Valid Integer as per is_numeric
✅ Valid Float as per is_float
✅ Valid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 22: (string)2e4
Integer converted Value: 20000
Float converted Value: 20000
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
❌ Invalid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 23: (double)1337
Integer converted Value: 1337
Float converted Value: 1337
✅ Valid Integer as per is_numeric
✅ Valid Float as per is_float
✅ Valid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 24: (string)1e3
Integer converted Value: 1000
Float converted Value: 1000
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
❌ Invalid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 25: (double)10
Integer converted Value: 10
Float converted Value: 10
✅ Valid Integer as per is_numeric
✅ Valid Float as per is_float
✅ Valid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 26: (double)1.3
Integer converted Value: 1
Float converted Value: 1.3
✅ Valid Integer as per is_numeric
✅ Valid Float as per is_float
❌ Invalid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 27: (string)1.4
Integer converted Value: 1
Float converted Value: 1.4
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
❌ Invalid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 28: (string)1t
Integer converted Value: 1
Float converted Value: 1
❌ Invalid Integer as per is_numeric
❌ Invalid Float as per is_float
❌ Invalid Integer as per filter validate
❌ Invalid Float as per filter validate
----
Test Value 29: (string)1.5n
Integer converted Value: 1
Float converted Value: 1.5
❌ Invalid Integer as per is_numeric
❌ Invalid Float as per is_float
❌ Invalid Integer as per filter validate
❌ Invalid Float as per filter validate
----
Test Value 30: (integer)26
Integer converted Value: 26
Float converted Value: 26
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
✅ Valid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 31: (string)0x539
Integer converted Value: 0
Float converted Value: 0
❌ Invalid Integer as per is_numeric
❌ Invalid Float as per is_float
❌ Invalid Integer as per filter validate
❌ Invalid Float as per filter validate
----
Test Value 32: (integer)34
Integer converted Value: 34
Float converted Value: 34
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
✅ Valid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 33: (string)042
Integer converted Value: 42
Float converted Value: 42
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
❌ Invalid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 34: (integer)42
Integer converted Value: 42
Float converted Value: 42
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
✅ Valid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 35: (integer)-42
Integer converted Value: -42
Float converted Value: -42
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
✅ Valid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 36: (string)+42
Integer converted Value: 42
Float converted Value: 42
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
✅ Valid Integer as per filter validate
✅ Valid Float as per filter validate
----
Test Value 37: (string)-42
Integer converted Value: -42
Float converted Value: -42
✅ Valid Integer as per is_numeric
❌ Invalid Float as per is_float
✅ Valid Integer as per filter validate
✅ Valid Float as per filter validate
----

Author: Harshvardhan Malpani

PHP Developer based in New Delhi, India. Working as a freelance web developer providing server deployment, website development and maintenance services.

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