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5. Blocks Coding with Raspberry Pi
Variables
Variables

This documentation explains how to change and modify the value of variables, providing guidance on variable manipulation techniques.

Changing the Value of a Variable

Set … to

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>count</variable></variables><block type=\"variables_set\" disabled=\"true\" x=\"22\" y=\"202\"><field name=\"VAR\">count</field><value name=\"VALUE\"><shadow type=\"math_number\" disabled=\"true\"><field name=\"NUM\">0</field></shadow></value></block></xml>"}

This block is used to set the variable to be same as the value.

Parameters:

  • Screen Item
  • Condition: Number (Default: 0)

Output: N/A
Sample code:

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>count</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">count</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">3</field></shadow></value><next><block type=\"basic_consoleLogNum\"><value name=\"num\"><block type=\"variables_get\"><field name=\"VAR\">count</field></block></value></block></next></block></statement></block></xml>"}

The output:

Set - Result

Modifying the Value of a Variable

Change … by

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>count</variable></variables><block type=\"variables_change\" disabled=\"true\" x=\"23\" y=\"247\"><field name=\"VAR\">count</field><value name=\"VALUE\"><shadow type=\"math_number\" disabled=\"true\"><field name=\"NUM\">1</field></shadow></value></block></xml>"}

This block is used to change the variable by the amount of the number.

Parameters:

  • Screen Item
  • Condition: Number (Default: 0)

Output: N/A
Sample code:

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>count</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">count</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">3</field></shadow></value><next><block type=\"variables_change\"><field name=\"VAR\">count</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">1</field></shadow></value><next><block type=\"basic_consoleLogNum\"><value name=\"num\"><block type=\"variables_get\"><field name=\"VAR\">count</field></block></value></block></next></block></next></block></statement></block></xml>"}

The output:

Change - Output

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