Tips to avoid for loops
PythonSpeed/PerformanceTips - Python Wiki
https://wiki.python.org/moin/PythonSpeed/PerformanceTips#Loops
map operator,list comprehension,generater
Use More Iterators
https://nvie.com/posts/use-more-iterators/
iterator
python - Using numpy arrays to avoid for loops - combinatorics - Stack Overflow
https://stackoverflow.com/questions/38546628/using-numpy-arrays-to-avoid-for-loops-combinatorics
itertools
numpy.fromfunction
Pythonで多重forループを避ける簡単な手法 - Qiita
https://qiita.com/m-naoki/items/6bca118c564a68bb17b8
multiprocessing - what is the neat way to divide huge nested loops to 8(or more) processes using Python? - Stack Overflow
https://stackoverflow.com/questions/6576515/what-is-the-neat-way-to-divide-huge-nested-loops-to-8or-more-processes-using-p/6576565#6576565
Use numpy.fromfunction to avoid for-loop | Vanessa's Imiloa
https://imiloainf.wordpress.com/2011/08/01/use-numpy-fromfunction-to-avoid-for-loop/