TypeError：無法連接'str'和'float'對象

Question

我已經搜索並找不到如何解決這個問題，或者如何解決它。任何幫助表示讚賞，謝謝。

我的代碼如下：

def main(): 
temperature = raw_input("Please enter an integer followed by a single space then either a F for Fahrenheit, C for Celsius, K for Kelvin, or R for Rankine: ") 
    # algorithm for Farenheit to Kelvin, Celsius, and Rankine 
    if temperature[-1] == "F": 
    K = (temperature[:-1] + (459.67) * (5.0/9.0)) 
    print K 
    C = (temperature[:-1] - 32) * (5.0/9.0) 
    print C 
    R = (temperature[:-1] + 459.67) 
    print R 
    # algorithm for Celsius to Kelvin, Fahrenheit, and Rankine 
    elif temperature[-1] == "C": 
     K = (temperature[:-1] + 273.15) 
     print K 
     F = (temperature[:-1] * (9.0/5.0) + 32) 
     print F 
     R = (temperature[:-1] + 273.15) * (9.0/5.0) 
     print R 
    # algorithm for Kelvin to Celsius, Fahrenheit, and Rankine 
    elif temperature[-1] == "K": 
     C = (temperature[:-1] - 273.15) 
     print C 
     F = (temperature[:-1] * (9.0/5.0) - 459.67) 
     print F 
     R = (temperature[:-1] * (9.0/5.0)) 
     print R 
    # algorith for Rankine to Fahrenheit, Celsius, and Kelvin 
    elif temperature[-1] == "R": 
     F = (temperature[:-1] - 459.67) 
     print F 
     C = (temperature[:-1] - 491.67) * (5.0/9.0) 
     print C 
     K = (temperature[:-1] * (5.0/9.0)) 
     print K 
main() 

和我的錯誤消息我進入後「50 F」：

請輸入一個整數，其後由單個空間然後或者華氏，C A F爲攝氏，K爲開爾文，或R爲蘭金：50°F

Traceback (most recent call last): 
    File "/Users/Minotza/Documents/multi-unit_temperature_converter.py", line 36, in <module> 
    main() 
    File "/Users/Minotza/Documents/multi-unit_temperature_converter.py", line 5, in main 
    K = (temperature[:-1] + (459.67) * (5.0/9.0)) 
TypeError: cannot concatenate 'str' and 'float' objects 
>>> 

Answer 1

raw_input全部更換temperature[:-1]返回用戶輸入的string。你在找什麼是float。在Python中，無法將string和float對象一起添加。所以，你將不得不做的第一個輸入轉換爲float，以便您可以對其執行數學運算。

這是我會怎麼做：

user_input = raw_input("Prompt Text...").split(' ') 

temperature = float(user_input[0]) 
units_or_option = user_input[1] 

所以，split方法使一個列表出來什麼樣的用戶輸入，使用空格字符分割的條目。 temperature包含前面的第一件東西，鑄造成float。 units_of_option包含在數字和空格後輸入的字符。

因此，如果用戶輸入：

123.5 F 

變量的數值：

user_input = ["123.5", "F"] 
temperature = 123.5 
units_or_option = "F" 

Answer 2

temperature = raw_input("Please enter an integer followed by a single space then either a F for Fahrenheit, C for Celsius, K for Kelvin, or R for Rankine: ") 

raw_input返回一個字符串，所以你想分割字符串或將它轉換成每一步到一個浮動。

它總是最好設置爲變量的數量，而不是重複計算它的，所以你可以做第

將其轉換爲浮點數：

temperature = raw_input("Please enter an integer followed by a single space then either a F for Fahrenheit, C for Celsius, K for Kelvin, or R for Rankine: ") 
temp = float(temperature.split(' ')[0]) 

返回什麼string.split(obj)所做的是string的部分清單，將其與obj分開。例如，如果用戶輸入273 K，並因此temperature == '273 K',temperature.split(' ')通過在每個空間拆分它創建一個列表，該空間變爲['273', 'K']。但是，這些仍然是字符串，所以我們想將第一個轉換爲浮點數，所以我們做float(temperature.split(' ')[0]) # we only want to convert the first element。

你改進的代碼，用temp更換temperature[:-1]與unit更換temperature[-1]（它總是良好的編程習慣，以創建變量，而不是計算值多次）：

def main(): 
    temperature = raw_input("Please enter an integer followed by a single space then either a F for Fahrenheit, C for Celsius, K for Kelvin, or R for Rankine: ") 
    # algorithm for Farenheit to Kelvin, Celsius, and Rankine 
    temp, unit = float(temperature.split(' ')[0]), temperature[-1] # multi-assignment 
    if unit == "F": 
     K = (temp + (459.67) * (5.0/9.0)) 
     print K 
     C = (temp - 32) * (5.0/9.0) 
     print C 
     R = (temperature[:-1] + 459.67) 
     print R 
    # algorithm for Celsius to Kelvin, Fahrenheit, and Rankine 
    elif unit == "C": 
     K = (temp + 273.15) 
     print K 
     F = (temp * (9.0/5.0) + 32) 
     print F 
     R = (temp + 273.15) * (9.0/5.0) 
     print R 
    # algorithm for Kelvin to Celsius, Fahrenheit, and Rankine 
    elif unit == "K": 
     C = (temp - 273.15) 
     print C 
     F = (temp * (9.0/5.0) - 459.67) 
     print F 
     R = (temp * (9.0/5.0)) 
     print R 
    # algorith for Rankine to Fahrenheit, Celsius, and Kelvin 
    elif temperature[-1] == "R": 
     F = (temp - 459.67) 
     print F 
     C = (temp - 491.67) * (5.0/9.0) 
     print C 
     K = (temp * (5.0/9.0)) 
     print K 
main() 

Answer 3

你需要的只是2點的變化：
1：剛raw_input後
添加temperature=float(temperature.split(' ')[0]),temperature.split(' ')[1]爲temperature
例如：

temperature = raw_input("Please enter an integer followed by a single space then either a F for Fahrenheit, C for Celsius, K for Kelvin, or R for Rankine: ") 
temperature=float(temperature.split(' ')[0]),temperature.split(' ')[1] 
##. . . . your code 

第二：
與temperature[0]

您的最終代碼

def main(): 
    temperature = raw_input("Please enter an integer followed by a single space then either a F for Fahrenheit, C for Celsius, K for Kelvin, or R for Rankine: ") 
    # algorithm for Farenheit to Kelvin, Celsius, and Rankine 
    temperature=float(temperature.split(' ')[0]),temperature.split(' ')[1] 
    if temperature[-1] == "F": 
     K = (temperature[0] + (459.67) * (5.0/9.0)) 
     print K 
     C = (temperature[0] - 32) * (5.0/9.0) 
     print C 
     R = (temperature[0] + 459.67) 
     print R 
    # algorithm for Celsius to Kelvin, Fahrenheit, and Rankine 
    elif temperature[-1] == "C": 
     K = (temperature[0] + 273.15) 
     print K 
     F = (temperature[0] * (9.0/5.0) + 32) 
     print F 
     R = (temperature[0] + 273.15) * (9.0/5.0) 
     print R 
    # algorithm for Kelvin to Celsius, Fahrenheit, and Rankine 
    elif temperature[-1] == "K": 
     C = (temperature[0] - 273.15) 
     print C 
     F = (temperature[0] * (9.0/5.0) - 459.67) 
     print F 
     R = (temperature[0] * (9.0/5.0)) 
     print R 
    # algorith for Rankine to Fahrenheit, Celsius, and Kelvin 
    elif temperature[-1] == "R": 
     F = (temperature[0] - 459.67) 
     print F 
     C = (temperature[0] - 491.67) * (5.0/9.0) 
     print C 
     K = (temperature[0] * (5.0/9.0)) 
     print K 
main()