python 2.7从文本文件读取多行

Question

I have started to learn python, and have the question below. Please advise.

CZ:xxx
CZ:yyy
CZ:zzz
PD:EOL
CZ:uuu
CZ:vvv
CZ:www 
PD:EOL 

how to read the line show individually

CZ:xxx
CZ:yyy
CZ:zzz
PD:EOL

I tried the below coding.

with open('test.txt','r') as f
    for line in f:
        if 'CZ' in line:
            print line
            break

but only show the first line.... help

Answer 1

You have added break , which is not required.

with open('test.txt','r') as f
    for line in f:
        if 'CZ' in line:
            print line

Ouput:

CZ:xxx
CZ:yyy
CZ:zzz

If you want to display first 4 lines use enumerate

with open('test.txt', 'r') as f
    for index, line in enumerate(f):
        if index < 4 and 'CZ' in line:
            print line
            continue
        break

Answer 2

You can also use str.startswith

Ex:

with open(filename,'r') as f:
    for line in f:
        if line.startswith("CZ"):
            print line