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python针对关键字with/As怎样使用

改变量名,不要把变量名和关键字重名,变量名前可加_来区分,比如_type = "xxx"

with open('abc.txt','r') as f: balabalabala 等价于 try: f = open('abc.txt','r') except: pass else: balabalabala finally: f.close() 语法是不是简洁多了?

with open('abc.txt', 'r') as f: balabalabala 等价于 try: f = open('abc.txt', 'r') except: pass else: balabalabala finally: f.close() 语法是不是简洁多了?

比如打开一个文件 with open (filename,'r') as fp: for line in fp: print line with语句主要是实现打开和关闭简写为一条语句,上面的例子在for循环完成后 文件自动关闭

文件权限没打开?

try: with open("path/to/filename.file", "r") as f: pass # do with file handleexcept Exception as e: print(e) # do with exception

方法a要通过一实例来调用,如: class A: def a(self): print("I'm a") obj = A() obj.a()

#!/usr/bin/env python# coding: utf-8newLine = ""inFile, outFile = 'test.txt', 'result.txt'with open(inFile, 'r') as f1: with open(outFile, 'w') as f2: for n, line in enumerate(f1): if n % 3 == 0 and newLine: f2.write(newLine[:-...

你可以用系统的命令拷贝,如果你非要自己写程序的话,这种时候你需要node.js,方便而且省内存。 function copyBigFile(from,to){var fs=require('fs');var fromFile=fs.createReadStream(from);var copied=0;fromFile.on('data',function(data){...

把你的代码改一下 f = open("test.txt", "r") while True: line = f.readline() if line: pass # do something here line=line.strip() p=line.rfind('.') filename=line[0:p] print "create %s"%line else: breakf.close()写得可能罗嗦些,就是...

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