Adjust for() loops

Note

The Macro to Python converter is available from Metview version 5.22.0

For loops in Macro are normally converted into Python using a for loop with range():

Macro code

Generated Python code

 
for i=1 to 11 by 2 do
     print(i)
end for

for i in range(1, 12, 2):
     print(i)

However, in Macro the start, stop or step can also be a float, but the Python range() only supports ints. Therefore, when the converter is able to detect the presence of floats the loop is converted into Python using the numpy arange() method:

Macro code

Generated Python code

 
for i=1 to 4 by 0.5 do
     print(i)
end for

import numpy as np

for i in np.arange(float(1), float(4+0.5/2), float(0.5)):
     print(i)

Unfortunately, there are cases when start, stop or step hold float values but the converter cannot detect this and the loop is converted into Python using range(). In this case manual correction is needed as illustrated in the following example:

Macro code

Generated Python code

Correct Python code

 
step = 0.5
for i=2 to 6 by step do
    print(i)
end for

step = 0.5
# wrong
for i in range(2, 6 + step, step):
    print(i)

import numpy as np

step = 0.5
# correct
for i in np.arange(2, 6 + step/2., step):
    print(i)