如何在Python中的字符串后面和前面添加字符？

Question

我有两个变量，一个是string，另一个是list。你知道吗

string_val = 'CreateTime:1557770979668  {"schema":{"type":"string","optional":false},"payload":"{\"subscriptionId\":\"//blp/mktdata/BLOOMBERG IDENTIFIER?fields=LAST_PRICE\",\"MarketDataEvents\":{\"LAST_PRICE\":50.84}}"}'
list_val = ["25746UCY3 Corp","BBG00JM9XLN6 Equity","CFM0987JKM Pro"]

在所需的输出中，可以插入列表值的元素，而不是“BLOOMBERG IDENTIFIER”。我试过下面的代码，但没有成功。你知道吗

for i in range(0,len(list_val)):
    print(len(list_val))
    expect_val = string_val.split('mktdata/',0)[1]  + list_val[i] + string_val.split('?fields',0)[-1]
    print(expect_val)

期望输出：

CreateTime:1557770979668    {"schema":{"type":"string","optional":false},"payload":"{\"subscriptionId\":\"//blp/mktdata/25746UCY3 Corp?fields=LAST_PRICE\",\"MarketDataEvents\":{\"LAST_PRICE\":50.84}}"}
CreateTime:1557770979668    {"schema":{"type":"string","optional":false},"payload":"{\"subscriptionId\":\"//blp/mktdata/BBG00JM9XLN6 Equity?fields=LAST_PRICE\",\"MarketDataEvents\":{\"LAST_PRICE\":50.84}}"}
CreateTime:1557770979668    {"schema":{"type":"string","optional":false},"payload":"{\"subscriptionId\":\"//blp/mktdata/CFM0987JKM Pro?fields=LAST_PRICE\",\"MarketDataEvents\":{\"LAST_PRICE\":50.84}}"}

请建议，我怎样才能做到这一点？你知道吗

Answer 1

您可以使用.replace(x, y)：

string_val = 'CreateTime:1557770979668  {"schema":{"type":"string","optional":false},"payload":"{\"subscriptionId\":\"//blp/mktdata/BLOOMBERG IDENTIFIER?fields=LAST_PRICE\",\"MarketDataEvents\":{\"LAST_PRICE\":50.84}}"}'
list_val = ["25746UCY3 Corp","BBG00JM9XLN6 Equity","CFM0987JKM Pro"]
for x in list_val:
    print(string_val.replace('BLOOMBERG IDENTIFIER', x))

输出：

CreateTime:1557770979668  {"schema":{"type":"string","optional":false},"payload":"{"subscriptionId":"//blp/mktdata/25746UCY3 Corp?fields=LAST_PRICE","MarketDataEvents":{"LAST_PRICE":50.84}}"}
CreateTime:1557770979668  {"schema":{"type":"string","optional":false},"payload":"{"subscriptionId":"//blp/mktdata/BBG00JM9XLN6 Equity?fields=LAST_PRICE","MarketDataEvents":{"LAST_PRICE":50.84}}"}
CreateTime:1557770979668  {"schema":{"type":"string","optional":false},"payload":"{"subscriptionId":"//blp/mktdata/CFM0987JKM Pro?fields=LAST_PRICE","MarketDataEvents":{"LAST_PRICE":50.84}}"}