基于另一列中的值计算一列中字符串的出现次数

Question

对于这个非常基本的问题，我提前表示歉意，我知道到处都有关于这个问题的帖子，但我似乎无法在其他网页上得到所有的帮助。你知道吗

首先，我是python的初学者，很抱歉代码太模糊了。但我只想计算某个字符串在第2列中出现的次数，而第1列中的值保持不变。如果这个值改变，循环应该重新开始。这听起来很简单，但是python将我的文本文件作为字符串来读取（给我带来了strip和split等问题）让我很困惑。我似乎无法让这个代码工作。请有人帮帮这个遇险的家伙！你知道吗

输入：

    6    ABMV
    6    ABMV
    6    FOOD
    6    FOOD
    6    IDLE
    10    IDLE
    10    ABMV
    10    IDLE

代码：

    #! /usr/bin/env python

    from collections import Counter

    outfile = open ("counts_outfile.txt", "w")

    with open("test_counts.txt", "r") as infile:
        lines = infile.readlines()
        for i, item in enumerate(lines):
        lines[i] = item.rstrip().split('\t')
        last_chimp = lines[0][0]
        behavior = lines[0][1]
        nr_ABMV = 0
        nr_FOOD = 0
        nr_IDLE = 0

        for lines in infile:
            chimp = lines[0][0]
            behavior = lines[0][1]
            if chimp == last_chimp:
                if behavior == "ABMV":
                    nr_ABMV += 1
                elif behavior == "FOOD":
                    nr_FOOD += 1
                elif behavior == "IDLE":
                    nr_IDLE += 1
                else:
                    continue
        else:
            outline = "chimp_header %s\t%s\t%s\t%s" % (last_chimp, nr_ABMV, nr_FOOD, nr_IDLE)
            outfile.write(outline)
            last_chimp == lines[0][0]
            nr_ABMV = 0
            nr_FOOD = 0
            nr_IDLE = 0

    outfile.close()

事先谢谢你，你会帮我的，显然还有很多‘黑猩猩’（黑猩猩）很多！！你知道吗

谨致问候

Answer 1

下面是一个与您的代码非常相似的示例：

outfile = open ("counts_outfile.txt", "w")
outfile.write("chimp_header {:>4} {:4} {:4} {:4}\r\n".format('chimp', 'ABMV', 'FOOD', 'IDLE'))

with open("test_counts.txt", "r") as infile:
    lines = [ line.strip() for line in infile if line.strip() ]

last_chimp = lines[0].split()[0]
behavior = { "ABMV":0, "FOOD":0, "IDLE":0 }

for line in lines : 
    line_split = line.strip().split() 
    chimp = line_split[0]

    if chimp != last_chimp : 
        outfile.write("chimp_header {:>4} {:4} {:4} {:4}\r\n".format(last_chimp, behavior["ABMV"], behavior["FOOD"], behavior["IDLE"]))
        last_chimp = chimp
        behavior = { "ABMV":0, "FOOD":0, "IDLE":0 }
    behavior[line_split[1]] += 1

outfile.write("chimp_header {:>4} {:4} {:4} {:4}\r\n".format(last_chimp, behavior["ABMV"], behavior["FOOD"], behavior["IDLE"]))
outfile.close()

下面是另一个使用Counter和字典的示例：

from collections import Counter

with open("test_counts.txt", "r") as infile:
    lines = [ tuple(line.strip().split()) for line in infile if line.strip() ]

chimps = { line[0] : { "ABMV":0, "FOOD":0, "IDLE":0 } for line in lines }
for k, v in Counter(lines).items() :
    chimps[k[0]][k[1]] = v

with open("counts_outfile.txt", "w") as outfile : 
    outfile.write("chimp_header {:>4} {:4} {:4} {:4}\r\n".format('chimp', 'ABMV', 'FOOD', 'IDLE'))
    for chimp in chimps : 
        outfile.write("chimp_header {:>4} {:4} {:4} {:4}\r\n".format(chimp, chimps[chimp]["ABMV"], chimps[chimp]["FOOD"], chimps[chimp]["IDLE"]))

两个例子产生相同的结果：

chimp_header chimp ABMV FOOD IDLE
chimp_header    6    2    2    1
chimp_header   10    1    0    2

我希望这能给你一些想法。你知道吗