如何在Python 3.2中的txt文件中记录“ Y”的出现

Question

I'm trying to record how many times the letter Y appears in the 6th column of a .txt file and assign that to a variable. How would I go about doing that? Thx in advance!

.txt file:

119,29/12/15,18:00,Ripley,Magnitude,Y,Magnitude               
120,30/12/15,18:00,Jenkins,Kes,Y,Kes                    
121,31/12/15,18:00,Big Boss,Ingsoc,Y,Ingsoc                
122,01/01/16,18:00,Einstein100,RNGesus,,             
123,02/01/16,18:00,Macho Man,Napoleon Wilson,,               
124,03/01/16,18:00,Dennis,Billy Casper,, 

I've set the whole file to a variable and have created variables for each column in the file.

    NextRecord = data[x]
    Number = NextRecord[0]
    Date = NextRecord[1]
    Time = NextRecord[2]
    P1Nickname = NextRecord[3]
    P2Nickname = NextRecord[4]
    Status = NextRecord[5]

Answer 1

Use csv and sum :

import csv

with open(filename) as records:
    reader = csv.reader(records)
    print(sum(row[5] == 'Y' for row in reader))

Your data is comma separated, and Python has the csv module for working with delimited values (could be semicolon separated, etc, as well).

The reader is iterable and yields a row at a time.

I've used the sum function which takes an iterable but I've used a generator expression to yield True or False for each row in the file.

The expression row[5] == 'Y' evaluates either True or False . When you give a boolean value to sum it converts to an integer and True becomes 1 , False becomes 0 . We could have written it as:

sum(1 for row in reader
    if row[5] == 'Y')

This however is slightly different. It filters out only the rows which have Y in the 6th column and yields the value 1 for each of those rows. It's subtly different.

Answer 2

You should try using the csv module:

import csv

counter = 0
with open("data.csv","r") as fi:
    inCsv = csv.reader(fi,delimiter=',')
    for row in inCsv:
        if (row[5].strip() == 'Y'):
            counter += 1
print ("Y count: " + str(counter))

Answer 3

THIS should work as expected:

noOfY=0
for line in open("thatTextFile.txt"): 
    try: 
        if 'Y' in line.split(',')[5]: noOfY+=1
    except:
        pass
print(noOfY)

This gives for the text provided above:

3

and works even in case of malformed lines in the input text file.