Databases
StackOverflow2013
Postsdbo
POPython - Evaluating a string expression in a string
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POPython - Evaluating a string expression in a string
    primarykey
    data
    text
    <p>I am trying to do something like this </p> <p><a href="https://stackoverflow.com/questions/2371436/evaluating-a-mathematical-expression-in-a-string">Evaluating a mathematical expression in a string</a> </p> <p><strong>Update - Some details about the app</strong></p> <p>The app 'exposes' some variables to the users. An example of an exposed variable is user_name. The user of the app can then create a new variable called 'user_name_upper' that can be set as user_name.upper(). Another example is exposed variables first_name and last_name and the user can create a new variable called 'full_name = last_name.upper() + ',' + first_name.upper()'. This is entered using a input box UI element. So no hooks into the program. Or think of this as a report like excel where I can create a new column to be a manipulation of some already defined variables.</p> <p>The users of this app are not programmers. But they can be given a list of examples to find their way around string manipulations</p> <p>However, my expression will be used for string manupulation. Something like "string3 = string1 + string2". Here I'd like set the value of string3 to the value of string1 appended with string2. Or "string1 = string2.lower()"</p> <p>I have researched and have come to the conclusion that eval can be used but is very dangerous. From what I understand, ast_literal_eval() will not work with string manipulation methods like lower() as described here <a href="https://stackoverflow.com/questions/12080197/why-does-this-string-not-work-with-ast-literal-eval">Why does this string not work with ast.literal_eval</a> </p> <p>Any suggestion on how to go about this?</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USCommunity
    1. USShreyas
    plurals
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. COWhy are you trying to do this? There is probably a better way to organize your problem from the beginning so that this isn't necessary.
      singulars
      1. POPython - Evaluating a string expression in a string
      1. USAndrew Clark
    2. COThis is for a scientific app. Users will have the option of 'creating' their own variables and so this will involve user input that needs to be sanitized. What other way would you recommend?
      singulars
      1. POPython - Evaluating a string expression in a string
      1. USShreyas
    3. COLet the users write python scripts using your library
      singulars
      1. POPython - Evaluating a string expression in a string
      1. USpiokuc
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload