Hello, guys! I am new to Julia. Help me please. I want to change my string initialized in upper local scope, and then use it there text = "abacaba" text_result = "" #string must be changed for rule in 1:5 if i % 2 == 1 #some condition text_result = replace(text, "a" => "b", count=1) #this is another string end end print(text_result) # empty string will be printed

To re-assign the global variable text_result you need global in the loop. I highly recommend creating a function around this loop with text_result as an input (in which case you do not need global).

If the loop is not inside a function you need to declare test_results as a global AFAIK: text = "abacaba" text_result = "" #string must be changed for rule in 1:5 if i % 2 == 1 #some condition global text_result = replace(text, "a" => "b", count=1) #this is another string end end print(text_result) # not empty string will be printed

[image] sergeypospelov: Hello, guys! I am new to Julia. The best advice is to use Jupyter, which does not have this issue. The code will work the way that is intuitive. Otherwise, put any for loops in a function when working in the REPL or a .jl file. If you follow those rules and ever have to write global, then (as a beginner) you are probably are doing something you shouldn’t

[image] jlperla: The best advice is to use Jupyter, which does not have this issue. Nah, this is not “the best advice”. The best advice is exactly what happened here, someone learned about what a global variable is and how to change it’s binding and then went on coding exactly as before. There is absolutely no need to completely change your coding environment because of this.

[image] kristoffer.carlsson: The best advice is exactly what happened here, The best advice is to make a new user learn about a complicated and frequently hated scoping rule that is only beloved by people who commit to core compiler? Furthermore, one which is completely alien to every other language the user may come from? Or, alternatively, get started in a the beginner friendly environment and hope people eventually fix this problem - as has been discussed for a year. I stick with my advice: Use jupyter, and wrap things in functions when you are not in jupyter.

[image] jlperla: The best advice is to use Jupyter, which does not have this issue. Sorry if we seem to be jumping all over you here, but bear in mind, there are some of us who absolutely detest Jupyter, I don’t think it’s a great idea to give people the impression that there is somehow something wrong with Julia outside of Jupyter. Of course, if someone wanted to use it anyway, it’s great to present it as an option.

[image] jlperla: The best advice is to make a new user learn about a complicated and frequently hated scoping rule that is only beloved by people who commit to core compiler? Complicated? It took one sentence and the reply was marked as a solution. Anyway, I am not going to pollute this thread further, I just didn’t want a bad advice stand uncontested.

[image] ExpandingMan: I highly recommend creating a function around this loop with text_result as an input (in which case you do not need global ). Why would you use text_result as an input? Strings are immutable, so you cannot change them. The scoping issue seems to me a red herring. for rule in 1:5 if i % 2 == 1 # what is i supposed to be here?? text_result = replace(text, "a" => "b", count=1) #this is another string end end This code just takes text and replaces the first ‘a’ with ‘b’, over and over. You can replace your code with this function: textrep(text) = replace(text, "a"=>"b", count=1) Actually, you should use characters instead of strings in the replace call, since it is faster: textrep(text) = replace(text, 'a'=>'b', count=1) In summary: There is no point in pre-allocating text_result because it just gets thrown away each time you assign the output from replace to it.

[image] DNF: Why would you use text_result as an input? Sorry, I meant text.

How to change string in local scope

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How to change string in local scope

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