一、int函数能够

     （1）把符合数学格式的数字型字符串转换成整数

     （2）把浮点数转换成整数，但是只是简单的取整，而非四舍五入。

1 aa = int("124")    #Correct 2 print "aa = ", aa  #result=124 3 bb = int(123.45) #correct 4 print "bb = ", bb #result=123 5 cc = int("-123.45")  #Error,Can't Convert to int 6 print "cc = ",cc 7 dd = int("34a")    #Error,Can't Convert to int 8 print "dd = ",dd 9 ee = int("12.3") #Error,Can't Convert to int10 print ee

 二、float函数将整数和字符串转换成浮点数。

aa = float("124")     #Correctprint "aa = ", aa     #result = 124.0 bb = float("123.45")  #Correctprint "bb = ", bb     #result = 123.45cc = float(-123.6)    #Correctprint "cc = ",cc      #result = -123.6dd = float("-123.34") #Correctprint "dd = ",dd      #result = -123.34ee = float('123v')    #Error,Can't Convert to floatprint ee

 三、str函数将数字转换成字符

aa = str(123.4)     #Correctprint aa            #result = '123.4'bb = str(-124.a)    #SyntaxError: invalid syntaxprint bbcc = str("-123.45") #correctprint cc            #result = '-123.45'dd = str('ddd')     #correctprint dd            #result = dddee = str(-124.3)    #correctprint ee            #result = -124.3