Python - 简化重复的 if 语句

Question

我是 python 的新手，正在寻找一种方法来简化以下内容:

if atotal == ainitial:
    print: "The population of A has not changed"
if btotal == binitial:
    print: "The population of B has not changed"
if ctotal == cinitial:
    print: "The population of C has not changed"
if dtotal == dinitial:
    print: "The population of D has not changed"

显然 _total 和 _initial 是预定义的。在此先感谢您的帮助。

Answer 1

您可以使用两个词典:

totals   = {'A' : 0, 'B' : 0, 'C' : 0, 'D' : 0}
initials = {'A' : 0, 'B' : 0, 'C' : 0, 'D' : 0}
for k in initials:
    if initials[k] == totals[k]:
        print "The population of {} has not changed".format(k)

类似的方法是先确定未变化的种群:

not_changed = [ k for k in initials if initials[k] == totals[k] ]
for k in not_changed:
    print "The population of {} has not changed".format(k)

或者，你可以有一个单一的结构:

info = {'A' : [0, 0], 'B' : [0, 0], 'C' : [0, 0], 'D' : [0, 0]} 
for k, (total, initial) in info.items():
    if total == initial:
        print "The population of {} has not changed".format(k)