打印包含指定关键字的csv文件行

Question

我是Python新手，但我想对一些csv文件做一些数据分析。我想打印csv文件中只包含一些关键字的行。我使用第一个块打印所有有效的行。从这些行我想打印的那些包括关键字。谢谢你的帮助。在

csv.field_size_limit(sys.maxsize)
invalids = 0
valids = 0
for f in ['1.csv']:
    reader = csv.reader(open(f, 'rU'), delimiter='|', quotechar='\\')
    for row in reader:
        try:
            print row[2] 
            valids += 1
        except:
            invalids += 1
print 'parsed %s records. ignored %s' % (valids, invalids)

使用关键字：

^{pr2}$

我想我需要用if语句来过滤我的顶级代码，但是我已经为此苦苦挣扎了几个小时，似乎无法让它正常工作。在

Answer 1

你的猜测是正确的。您只需使用if语句筛选行，检查每个字段是否匹配关键字。下面是您的方法（我还对您的代码做了一些改进，并在注释中进行了解释）：

# First, create a set of the keywords. Sets are faster than a list for
# checking if they contain an element. The curly brackets create a set.
keywords = {'ford', 'hyundai','honda', 'jeep', 'maserati','audi','jaguar',
            'volkswagen','chevrolet','chrysler'}
csv.field_size_limit(sys.maxsize)
invalids = 0
valids = 0
for filename in ['1.csv']:
    # The with statement in Python makes sure that your file is properly closed
    # (automatically) when an error occurs. This is a common idiom.
    # In addition, CSV files should be opened only in 'rb' mode.
    with open(filename, 'rb') as f:
        reader = csv.reader(f, delimiter='|', quotechar='\\')
        for row in reader:
            try:
                print row[2] 
                valids += 1
            # Don't use bare except clauses. It will catch
            # exceptions you don't want or intend to catch.
            except IndexError:
                invalids += 1
            # The filtering is done here.
            for field in row:
                if field in keywords:
                    print row
                    break
# Prefer the str.format() method over the old style string formatting.
print 'parsed {0} records. ignored {1}'.format(valids, invalids)