Seite - 43 - in Programming for Computations – Python - A Gentle Introduction to Numerical Simulations with Python 3.6, Band Second Edition

2.2 Variables,ObjectsandExpressions 43 In [1]: x = 2 In [2]: y = 4.0 In [3]: s = ’hello’ In [4]: type(x) # ...object named x is an integer Out[4]: int In [5]: type(y) # ...object named y is a float Out[5]: float In [6]: type(s) # ...object named s is a string Out[6]: str Type Conversion Objects may be converted from one type to another if it makes sense. If, e.g.,x is thenameofanintobject,writing In [1]: x = 1 In [2]: y = float(x) In [3]: y Out[3]: 1.0 shows thaty thenbecomesa floatingpoint representationofx. Similarly,writing In [1]: x = 1.0 In [2]: y = int(x) In [3]: y Out[3]: 1 illustrates thatybecomesan integer representationofx. Note that theint function rounds down, e.g., y = int(1.9) also makes y become the integer 1. Type conversionmayalsooccurautomatically. 2.2.5 AutomaticTypeConversion What if weaddafloat object to an intobject?We could,e.g.,write In [1]: x = 2 In [2]: x = x + 4.0 In [3]: x Out[3]: 6.0 What happens here, is that automatic type conversion takes place, and the new x will have thevalue6.0, i.e., refer to anobjectof typefloat.