check if lowercase ruby code example

Example 1: js check if string is number

isNaN(num)         // returns true if the variable does NOT contain a valid number

isNaN(123)         // false
isNaN('123')       // false
isNaN('1e10000')   // false (This translates to Infinity, which is a number)
isNaN('foo')       // true
isNaN('10px')      // true

Example 2: check if string is empty python

my_str = ""
if not my_str:
  print("empty")
else:
  print("not empty")
#output: empty