How to search string for multiple values?

Question

This code works:

if ((filenameTmp == "thunderstorm") || 
   (filenameTmp == "fog") || 
   (filenameTmp == "hail") ||
   (filenameTmp == "heavy_snow") ||
   (filenameTmp == "rain") ||
   (filenameTmp == "sleet") ||
   (filenameTmp == "snow"))
{ document.getElementById("twilightBG").style.display = "none"; }

However I would like to shorten it, I thought this would work but it doesn't.

if(filenameTmp.indexOf ("thunderstorm", "fog", "hail", "heavy_snow", "haze", "sleet", "snow")> -1)
{ document.getElementById("twilightBG").style.display = "none"; }

It does work if I only have a single search like this:

if(filenameTmp.indexOf ("haze")> -1)
{ document.getElementById("twilightBG").style.display = "none"; }

How can I do it searching for multiple instances? Or is there a better way? Thanks.

Are you using Jquery as well, or only pure javascript?

disappointed in SO leadership
– disappointed in SO leadership

2014-08-21 05:59:04 +00:00
Commented Aug 21, 2014 at 5:59 — disappointed in SO leadership
– disappointed in SO leadership, Commented Aug 21, 2014 at 5:59

T.J. Crowder · Accepted Answer · 2014-08-21 06:09:32Z

Three options for you:

A map object
An array lookup
switch

Details:

You can use a lookup map object:

// In a common declarations area
var weather = {
    "thunderstorm": true,
    "fog": true,
    "hail": true,
    "heavy_snow": true,
    "rain": true,
    "sleet": true,
    "snow": true
};

// Where you want the check
if (weather[filenameTmp]) {
    document.getElementById("twilightBG").style.display = "none";
}

Note that you can do that inline if you like:

if ({ "thunderstorm": true, "fog": true, "hail": true, "heavy_snow": true, "rain": true, "sleet": true, "snow": true }[filenameTmp]) {
    document.getElementById("twilightBG").style.display = "none";
}

Note that if filenameTmp has the value "toString", "valueOf", or similar, you'll get false-positives from that. If you're using a true ES5-enabled engine, you can get pure maps (objects that don't have toString and such) by using a builder function:

function pureMap(props) {
    var o = Object.create(null);
    var key;
    if (props) {
        for (key in props) {
            o[key] = props[key];
        }
    }
    return o;
}

Then:

// In a common declarations area
var weather = pureMap({
    "thunderstorm": true,
    "fog": true,
    "hail": true,
    "heavy_snow": true,
    "rain": true,
    "sleet": true,
    "snow": true
});

// Where you want the check
if (weather[filenameTmp]) {
    document.getElementById("twilightBG").style.display = "none";
}

Or you could use an array, but the search is linear whereas browsers can optimize the map lookup above:

// In a common declarations area
var weather = [
    "thunderstorm",
    "fog",
    "hail",
    "heavy_snow",
    "rain",
    "sleet",
    "snow"
];

// Where you want the check
if (weather.indexOf(filenameTmp) !== -1) {
    document.getElementById("twilightBG").style.display = "none";
}

And again, that can be inline:

if ([ "thunderstorm", "fog", "hail", "heavy_snow", "rain", "sleet", "snow" ].indexOf(filenameTmp) !== -1) {
    document.getElementById("twilightBG").style.display = "none";
}

There's also the switch option:

switch (filenameTmp) {
    case "thunderstorm":
    case "fog":
    case "hail":
    case "heavy_snow":
    case "rain":
    case "sleet":
    case "snow":
        document.getElementById("twilightBG").style.display = "none";
        break;
}

all right, but if (weather[filenameTmp]) is not the same of IndexOf > -1

Rahul Tripathi · Accepted Answer · 2014-08-21 05:57:52Z

4

You may use the array approach like this:

if (["thunderstorm", "fog", "hail", "heavy_snow", "haze", "sleet", "snow"].indexOf(filenameTmp) >= 0) {

answered Aug 21, 2014 at 5:57

Rahul Tripathi

173k33 gold badges292 silver badges341 bronze badges

2 Comments

Luca B. Over a year ago

This won't work in older browsers (ie < 8 to name one)

Nicoll Over a year ago

Thanks, I did try an array but I got the syntax wrong, this works perfect for my needs (iPhone only). This is the method I'm now using.

Luca B. · Accepted Answer · 2014-08-21 07:06:28Z

4

You can use the match() method together with a regex

var.match(^(?:apple|pear|whatever)$/)

edited Aug 21, 2014 at 7:06

answered Aug 21, 2014 at 6:01

Luca B.

6484 silver badges13 bronze badges

4 Comments

T.J. Crowder Over a year ago

+1, but you'll want anchors on that, and if you're not using the resulting match array it's better to use test: if (/^(?:thunderstorm|fog|hail|heavy_snow|rain|sleet|snow)$/.test(filenameTmp)) { /*...*/ }

Luca B. Over a year ago

won't your regex check for a string that IS "thunderstorm", "fog" etc.? If I understood it correctly the question asks to check if the string contains those words. (btw feel free to improve the answer if you wish so!)

T.J. Crowder Over a year ago

The OP's code in the question under "This code works:" is checking that the string is "thunderstorm," etc., not that it contains it.

Luca B. Over a year ago

My bad, reading the questions from mobile is really a pain. (Fixing the regex right now)

Amit Portnoy · Accepted Answer · 2014-08-21 05:58:15Z

3

if (["thunderstorm", "fog", "hail", "heavy_snow", "haze", "sleet", "snow"].indexOf(filenameTmp) !== -1) {
document.getElementById("twilightBG").style.display = "none";
}

answered Aug 21, 2014 at 5:58

Amit Portnoy

6,4362 gold badges32 silver badges31 bronze badges

Comments

Tapaswi Panda · Accepted Answer · 2014-08-21 06:23:38Z

2

The check would be cleaner if the contains method were added to Array.prototype directly:

Array.prototype.contains = function(obj) { return this.indexOf(obj) > -1; };

This allows the check to be:

if (['thunderstorm', 'fog', 'hail', 'heavy_snow', 'rain', 'sleet', 'snow'].contains(filenameTmp)) {
document.getElementById("twilightBG").style.display = "none";

}

answered Aug 21, 2014 at 6:23

Tapaswi Panda

1,0517 silver badges13 bronze badges

Comments

Khaleel · Accepted Answer · 2014-08-21 06:03:13Z

1

Use Array and loop through every entry . this is most efficient way .By this it ll not loop thru all entry once it encounter any one.

function containsAny(str, substrings) {
    for (var i = 0; i != substrings.length; i++) {
        var substring = substrings[i];
        if (str == substring) {
            return true;
        }
    }
    return null;
}

var result = containsAny(filenameTmp, ["thunderstrom", "rain"]); // add values you want
if (result) {
    document.getElementById("twilightBG").style.display = "none";
}

Hope this helps

answered Aug 21, 2014 at 6:03

Khaleel

1,4113 gold badges18 silver badges36 bronze badges

Comments

Amit Portnoy · Accepted Answer · 2014-08-21 06:05:40Z

1

For a bleeding edge solution use Set. Keep in mind it's not currently supported on Opera and Safari:

var weather = new Set();

weather.add("thunderstorm");
weather.add("fog");
weather.add("hail");
weather.add("heavy_snow");
weather.add("rain");
weather.add("sleet");
weather.add("snow");

if (weather.has(filenameTmp)) {
    document.getElementById("twilightBG").style.display = "none";
}

answered Aug 21, 2014 at 6:05

Amit Portnoy

6,4362 gold badges32 silver badges31 bronze badges

Comments

codeyu · Accepted Answer · 2014-08-21 06:18:01Z

1

You can use regx:

if (filenameTmp.match(/^(thunderstorm|fog|hail|heavy_snow|rain|sleet|snow)$/)) {
    document.getElementById("twilightBG").style.display = "none";
    }

or array of js 5:

if (['thunderstorm', 'fog', 'hail', 'heavy_snow','rain','sleet','snow'].indexOf(filenameTmp) >= 0) {
document.getElementById("twilightBG").style.display = "none";
}

or inArray method of Jquery:

if ($.inArray(filenameTmp, ['thunderstorm', 'fog', 'hail', 'heavy_snow','rain','sleet','snow']) >= 0) {
document.getElementById("twilightBG").style.display = "none";
}

answered Aug 21, 2014 at 6:18

codeyu

212 bronze badges

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