ESP8266 Community Forum

- Sat Sep 26, 2015 10:34 pm #29957 Hi, anyone tested the "String.substring()" function? I do not get it working. "String.replace" is fine. Want to eleminate redundate spaces of HTML-code in a string before sending:

Code: Select all while (html_index.substring(0) == "  ") {
   html_index.replace("  "," ");
 }

my ESP8266: ESP-01 V2 / ESP-12E (NodeMCU)
ESP8266 Arduino add-on
Arduino IDE 1.6.5

- Sun Sep 27, 2015 6:42 am #29971 I honestly think that the documentation for the String.substring() method could hardly be worse...

String.substring() does not "looks for a given substring from the position given to the end of the string"; it cuts a part of the string and lets you do whatever you want with that part. So, someString.substring(0) returns exactly the same as someString, because "someString.substring(0)" means "cut from the first character of someString, up to the end of someString".

In your code, (html_index.substring(0) == " ") is only true when html_index is exactly " "; far from what you need.

- Mon Sep 28, 2015 3:40 am #30036 OK,

sounds like I have to use strstr()

my ESP8266: ESP-01 V2 / ESP-12E (NodeMCU)
ESP8266 Arduino add-on
Arduino IDE 1.6.5

- Mon Sep 28, 2015 9:37 am #30049

sounds like I have to use strstr()

You should be able to use indexOf:

https://www.arduino.cc/en/Reference/StringIndexOf

-- John