读取文本文件中特定列和行中的数据

Question

I Have a text file which contain 3 columns and 20000 rows. I like to know what should I do to get the specific data (for example) in row 1000 and column 2? My first column is formatted like AAAA and my second column is a number like 1234. I tried this solution but I got an error based on my first column being letters I would like to define a variable which contains my data at the end:

with open ('my_file') as f:
    for x , line in eumerate(f):
         if x = 1000:
             numfloat = map(float , line.split())
             print numfloat[1]

Answer 1

You are trying to use float() on something that contains letters. this happens when you call:

numfloat = map(float , line.split()) 

You need to tell us the exact output that you are looking for but here is one possible solution

num_float = map(float, line.split()[1])

or better yet

num_float = float(line.split()[1])

This will only get you the middle column, I'm not certain if you need the entire row or not.

Additionally, as noted below, you need to change = to == in your if statement. = is for assigment, == is for comparison.

Answer 2

make '=' to '==' at line 3 of your code

with open('my_file', 'r') as f:
    for x, line in enumerate(f):
        if x == 1000:
            print float(line.split()[1])

Answer 3

import re

with open('my_file', 'r') as f:
    for x, line in enumerate(f):
        if x == 1000: 
            array = re.split('(\d+)',line) # array=['AAAA','123'] if line='AAAA123'
            print array[1] # your required second row.