python - 命令行python没有输出

Question

这是我的代码。当我运行它时，它只是在运行后退出。没有打印任何内容。为什么这样 ？

def checkString(filename, string):
    input = file(filename) # read only will be default file permission
    found = False
    searchString = string
    for line in input:
        if searchString in line:
            found = True
            break

if callfunc == 'initialize':
    print listdir() #this will print list of files
    print "\n"

for files in listdir():
    checkString(files,"hello")

if found:
    print "String found"
else:
    print "String not found"
input.close()

Answer 1

found是函数中的本地名称checkString()；它保持在本地，因为您不返回它。

从函数返回变量并存储返回值：

def checkString(filename, string):
    input = file(filename) # read only will be default file permission
    found = False
    searchString = string
    for line in input:
        if searchString in line:
            found = True
            break
    return found

for files in listdir():
    found = checkString(files,"hello")
    if found:
        print "String found"
    else:
        print "String not found"

Answer 2

您需要修改为：

def checkString(filename, string):
    input = file(filename) # read only will be default file permission
    found = False
    searchString = string
    for line in input:
        if searchString in line:
            found = True
            break

    input.close()
    return found

found = False

if callfunc == 'initialize':
    print listdir() #this will print list of files
    print "\n"

for files in listdir():
    found = found or checkString(files,"hello")

if found:
    print "String found"
else:
    print "String not found"

这是因为在您的原始文件found中仅在函数范围内checkString