## Checking if a string is a double or not

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I am trying to check in php if a string is a double or not.

Here is my code:

```   if(floatval(\$num)){
\$this->print_half_star();
}
```

\$num is a string..The problem is that even when there is an int it gives true. Is there a way to check if it is a float and not an int!?

```// Try to convert the string to a float
\$floatVal = floatval(\$num);
// If the parsing succeeded and the value is not equivalent to an int
if(\$floatVal && intval(\$floatVal) != \$floatVal)
{
// \$num is a float
}
```

Java Program to Check if a String is Numeric, Example 1: Check if a string is numeric​​ We also have a boolean value numeric which stores if the final result is numeric or not. To check if string contains numbers only, in the try block, we use Double 's parseDouble() method to convert the string to a Double . Else, it's a number. Perhaps the easiest and the most reliable way to check whether a String is numeric or not is by parsing it using Java's built-in methods: Integer.parseInt(String) Float.parseFloat(String) Double.parseDouble(String) Long.parseLong(String) new BigInteger(String)

This will omit integer values represented as strings:

```if(is_numeric(\$num) && strpos(\$num, ".") !== false)
{
\$this->print_half_star();
}
```

Check If a String Is Numeric in Java, Oftentimes while operating upon Strings, we need to figure out whether a String is a valid number or not. In this tutorial, we'll explore multiple  You can also count how many points your string contains. If this number is less or equal than 1 and if all other characters are numbers, your string is a valid double.

You can try this:

```function isfloat(\$num) {
return is_float(\$num) || is_numeric(\$num) && ((float) \$num != (int) \$num);
}

var_dump(isfloat(10));     // bool(false)
var_dump(isfloat(10.5));   // bool(true)
var_dump(isfloat("10"));   // bool(false)
var_dump(isfloat("10.5")); // bool(true)
```

How to check if a std: :string is a floating point number (in C++), How do you check if a string is a double C++? We also have a boolean value numeric which stores if the final result is numeric or not. To check if string contains numbers only, in the try block, we use Double 's parseDouble () method to convert the string to a Double. If it throws an error (i.e. NumberFormatException error), it means string isn't a number and numeric is set to false.

Why not use the magic of regular expression

```<?php
\$p = '/^[0-9]*\.[0-9]+\$/';
\$v = '89.00';
var_dump(preg_match(\$p, \$v));
\$v = '.01';
var_dump(preg_match(\$p, \$v));
\$v = '0.01';
var_dump(preg_match(\$p, \$v));
\$v = '89';
var_dump(preg_match(\$p, \$v));
```

Python String isnumeric() and its application, , and idx is an optional parameter that will point to the next character in str following the numerical value. The common approach would be to check it with a regular expression like it's also suggested inside the Double.valueOf (String) documentation. The regexp provided there (or included below) should cover all valid floating point cases, so you don't need to fiddle with it, since you will eventually miss out on some of the finer points.

if "double string format " like this "XXXXXX.XXXXXX"

try check

```function check_double_string(\$str){
\$pairs = explode('.',\$str);
if ( is_array(\$pairs) && count(\$pairs)==2) {
return ( is_numeric(\$pairs) && is_numeric(\$pairs)? true : false;
}
return false;
}
```

Check if a String is a valid Double, How do you check if a string is a number? Let’s discuss certain ways in which one can check if string is a float to avoid potential errors. Method #1 : Using isdigit () + replace () The combination of above function is used to perform this task and hence. This works in 2 steps, first the point value is erased and the string is joined to form a digit and then is checked.

Check if a given string is a valid number (Integer or Floating Point) in , How do you test if a string is a number python? bool valid = double.TryParse(text, style, culture, out result); Then use the validvariable to determine whether or not it was actually parsed correctly. If validis true, then the value of resultis the parsed value. If validis false, resultwill be 0.

How to check that a string is parse-able to a double in java?, How do you check whether the given input is string or not in Java? Dim value As Double If Double.TryParse(stringFromDataTable, value) Then ' text has been parsed as value, ' ' so you can use value however you see fit ' Else ' text was not a valid double, so you can ' ' notify the user or do whatever you want ' ' note that value will be zero in this case ' End If

check if String is parseable to Double, i is quite well-understood, but some may frown upon a single c to represent a character, or even str for your method argument I'm not suggesting  Teams. Q&A for Work. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information.

• It wasn't part of question but is a part of problem - this method shows `1.1aaa` is proper float value so in fact, it doesn't check if a string is a double or not.
• `isfloat("1e10")` returns true.