python - 排序值(for 循环)

Question

我正在使用 python 2.7 开发一个简单的核苷酸计数器，在我编写的其中一种方法中，我想打印 g、c、a、t 值按它们出现的次数排序在基因表中。有什么更好的方法可以做到这一点？提前致谢!

 def counting(self):
    gene = open("BRCA1.txt", "r")
    g = 0
    a = 0
    c = 0
    t = 0
    gene.readline()
    for line in gene:
        line = line.lower()
        for char in line:
            if char == "g":
                g += 1
            if char == "a":
                a += 1
            if char == "t":
                t += 1
            if char == "c":
                c += 1
    print "number of g\'s: %r" % str(g)
    print "number of c\'s: %r" % str(c)
    print "number of d\'s: %r" % str(a)
    print "number of t\'s: %r" % str(t)

Answer 1

使用 Counter类。

from collections import Counter
counter = Counter(char for line in gene for char in line.lower() )
for char, count in counter.most_common():
    print "number of %s\'s: %d" % (char, count)