Python學習筆記一:資料類型轉換

一、int函數能夠
     （1）把符合數學格式的數字型字串轉換成整數
     （2）把浮點數轉換成整數，但是只是簡單的取整，而非四捨五入。

 

舉例：

 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 int
10 print ee 
11 

二、float函數將整數和字串轉換成浮點數。

 

舉例：

 1 aa = float("124")     #Correct
 2 print "aa = ", aa     #result = 124.0 
 3 bb = float("123.45")  #Correct
 4 print "bb = ", bb     #result = 123.45
 5 cc = float(-123.6)    #Correct
 6 print "cc = ",cc      #result = -123.6
 7 dd = float("-123.34") #Correct
 8 print "dd = ",dd      #result = -123.34
 9 ee = float('123v')    #Error,Can't Convert to float
10 print ee 

 

三、str函數將數字轉換成字元

 

舉例：

 1 aa = str(123.4)     #Correct
 2 print aa            #result = '123.4'
 3 bb = str(-124.a)    #SyntaxError: invalid syntax
 4 print bb
 5 cc = str("-123.45") #correct
 6 print cc            #result = '-123.45'
 7 dd = str('ddd')     #correct
 8 print dd            #result = ddd
 9 ee = str(-124.3)    #correct
10 print ee            #result = -124.3

 

 

 

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