fname = input("Enter filename:") print #display a empty line #attempt to open file for reading try: fobj = open(fname, 'r') except IOError: print("file open error:") else: #display contents print('_ '*10,) for eachLine in fobj: print(eachLine,end = '') #end参数,默认为'\...
def myopen(file,mode='r'): try: fo = open(file,mode) except IOError,args: raise FileError, fileArgs(file, mode, args) return fo def testfile(): file = tempfile.mktemp() f = open(file,'w') f.close() for eachTest in ((0, 'r'), (0100, 'r'),(0400,'w'),(0500, 'w...
placing them in a loop, and executing the statement block once for each element extracted常见应用（Common applications）：计数循环（Counting loop）：遍历由range（）函数产生的数字序列，产生循环Traverse the sequence of numbers generated by the range() function, generating the loop字符串遍历循环（The st...
用each_line.split(":")这句话可以分解成A和I am a cool boy! 用(role,line_spoken) = each_line.split(“:”),来获取分解后的数据。 实例: data = open('DataFile.txt') for each_line in data: (role,line_spoken)=each_line.split(':') #需要缩进 print(role,end='') #缩进长度和上面一...
readlines([size]) -> list of strings, each a line from the file. Call readline() repeatedly and return a list of the lines so read. The optional size argument, if given, is an approximate bound on the total number of bytes in the lines returned. """ return [] def seek(self, offs...
# Write String to Text File in Text Mode text_file = open("D:/work/20190810/sample.txt", "wt") n = text_file.write('Python, Python~') text_file.close() print(n) 1. 2. 3. 4. 5. 执行和输出: 再次打开该文件查看其内容: ...
$ flake8 --helpusage: flake8 [options] file file ... positional arguments: filename optional arguments: -h, --helpshow thishelpmessageandexit -v, --verbose Print more information about whatishappeninginflake8. This optionisrepeatableandwill increase verbosity each time itisrepeated. ...
>>>f=fab(5)>>>f.next()1>>>f.next()1>>>f.next()2>>>f.next()3>>>f.next()5>>>f.next()Traceback(mostrecentcalllast):File"<stdin>",line1,in<module>StopIteration 当函数执行结束时,generator 自动抛出 StopIteration 异常,表示迭代完成。在 for 循环里,无需处理 StopIteration 异常,循环会...
a*7<49)print(8> a<=6)print(3== a>2)outputTrueFalseTrueTrueTrue9. ‘get’字典下面是访问Python字典中键值的传统方法：dict = {"P":1, "Q":2}print(dict["P"])print(dict["R"])代码的第三行会产生一个关键错误：Traceback (most recent call last):File ".\dict.py", line 3, inprint...
foreachincontent: print(each) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 分析 这里我是想要获取 div 的id含test的文本内容,于是写了//div[start-with(@id,"test")]/text()的xpath语句,运行时报了上面的错误,找了...