History of Idiom 22 > diff from v40 to v41

Edit summary for version 41 by :
New Scala implementation by user [meshelton]

↷

Version 40

2016-02-16, 21:28:08

Version 41

2016-02-18, 16:57:57

Idiom #22 Convert string to integer

Extract integer value i from its string representation s (in radix 10)

Idiom #22 Convert string to integer

Extract integer value i from its string representation s (in radix 10)

Code

I := Integer'Value (s);

Code

I := Integer'Value (s);

Rust

Rust

Code

let i = match s.parse::<i32>() {
  Ok(i) => i,
  Err(e) => {
    -1
  }
};

Code

let i = match s.parse::<i32>() {
  Ok(i) => i,
  Err(e) => {
    -1
  }
};

Comments bubble

s is parsed to 32-bits signed integer here (change number type if needed).
-1 is used here as a fallback value, but any error handling instructions can be used.

Comments bubble

s is parsed to 32-bits signed integer here (change number type if needed).
-1 is used here as a fallback value, but any error handling instructions can be used.

Pascal

Pascal

Imports

uses SysUtils;

Imports

uses SysUtils;

Code

var
  i: Integer;
 S: String;
begin
  S := '123';
  i := StrToInt(S);
end.

Code

var
  i: Integer;
 S: String;
begin
  S := '123';
  i := StrToInt(S);
end.

Comments bubble

The function StrToInt will raise an exception of type EConvertError if the string is not a proper representation of an integer.

Comments bubble

The function StrToInt will raise an exception of type EConvertError if the string is not a proper representation of an integer.

Rust

Rust

Code

let i: i32 = s.parse().unwrap_or(0);

Code

let i: i32 = s.parse().unwrap_or(0);

Comments bubble

This explicitly sets the value to 0 if it can't be parsed to an integer.

Comments bubble

This explicitly sets the value to 0 if it can't be parsed to an integer.

Demo URL

https://play.rust-lang.org/?code=fn%20main()%20%7B%0A%20%20%20%20let%20s%20%3D%20%2242%22%3B%0A%20%20%20%20let%20i%3A%20i32%20%3D%20s.parse().unwrap_or(0)%3B%0A%20%20%20%20%0A%20%20%20%20println!(%22%7B%7D%22%2C%20i)%3B%0A%7D%0A&version=stable

Demo URL

Imports

import std.conv;

Imports

import std.conv;

Code

auto i = s.to!int;

Code

auto i = s.to!int;

Comments bubble

The useful to function can convert just about anything to something else. It will throw on a non-integral input string.

Comments bubble

The useful to function can convert just about anything to something else. It will throw on a non-integral input string.

Rust

Rust

Code

let i = s.parse::<i32>().unwrap();

Code

let i = s.parse::<i32>().unwrap();

Comments bubble

This panics if s is not a valid number.
s is parsed to 32-bits signed integer here (change number type if needed).

Comments bubble

This panics if s is not a valid number.
s is parsed to 32-bits signed integer here (change number type if needed).

Code

i = 0+str;

Code

i = 0+str;

Comments bubble

JavaScript automatically converts a string to a number when you use it in a numeric expression.
(This also works with floating point numbers.)

Comments bubble

JavaScript automatically converts a string to a number when you use it in a numeric expression.
(This also works with floating point numbers.)

Perl

Perl

Code

my $s = "12";
my $i = $s + 13;   # Foo is now 25

Code

my $s = "12";
my $i = $s + 13;   # Foo is now 25

Comments bubble

Perl automatically converts numbers to strings, and strings to numbers, whenever required.

Comments bubble

Perl automatically converts numbers to strings, and strings to numbers, whenever required.

Imports

#include <cstdlib>

Imports

#include <cstdlib>

Code

int i = std::atoi(s);

Code

int i = std::atoi(s);

Comments bubble

s is a char*

Comments bubble

s is a char*

Doc URL

http://en.cppreference.com/w/cpp/string/byte/atoi

Doc URL

http://en.cppreference.com/w/cpp/string/byte/atoi

Ruby

Ruby

Code

i = s.to_i

Code

i = s.to_i

Comments bubble

to_i returns 0 if s is not a valid number.

Comments bubble

to_i returns 0 if s is not a valid number.

Doc URL

http://ruby-doc.org/core-2.3.0/String.html#to_i-method

Doc URL

http://ruby-doc.org/core-2.3.0/String.html#to_i-method

Java

Java

Code

int i = new Integer( s ).intValue();

Code

int i = new Integer( s ).intValue();

Comments bubble

This will throw NumberFormatException if s does not contain a parsable integer

Comments bubble

This will throw NumberFormatException if s does not contain a parsable integer

Doc URL

https://docs.oracle.com/javase/7/docs/api/java/lang/Integer.html#Integer%28java.lang.String%29

Doc URL

https://docs.oracle.com/javase/7/docs/api/java/lang/Integer.html#Integer%28java.lang.String%29

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History of Idiom 22 > diff from v40 to v41

Version 40

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Idiom #22 Convert string to integer

Idiom #22 Convert string to integer

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