Question 191701 in Flutter Question posted in
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Flutter – Can't concatenate two strings in dart

Here is my code:

onPressed: () {
  link = links[sessName.indexOf(str, 0)];
  print('$link.txt');
},

sessName – links array. For example, I will give the first element: 'http://lingvostim.com/LS2018/about'

I need to add a '.txt' to the end of link. I don’t know why string interpolation isn’t working. The console displays only 'http://lingvostim.com/LS2018/about'. I will be glad of your help.

Tags:

3

Answers


  1. 0

    If you try to print your value 'http://lingvostim.com/LS2018/about' directly, it should work fine. Just make sure your links[sessName.indexOf(str, 0)] expression returns expected value.

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  2. 0

    You should add null-aware operator ‘??’ to assign an empty string to the link variable if index not found. That is code after adding null-aware operator. Also you must define if link variable is String.

    onPressed: () {
  String link = links[sessName.indexOf(str)] ?? '';
  print('${link ?? ''}.txt');
},
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  3. 0

    Use parentheses with dollar for concatenation

    onPressed: () {
    link = links[sessName.indexOf(str, 0)]??';
    print('${link}.txt');
    }

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