如何將文本文件數據存儲為變量，然后使用這些變量計算值？

Question

我是 python 的新手，我有一個如下所示的文本文件：

0       10
0.01    10.0000001
0.02    10.00000113
0.03    10.00000468
0.04    10.0000128

分別是時間和速度的前幾個值。

我想將該文本文件讀入 Python 並使用這些值創建時間和速度變量，以便找到加速度。

到目前為止我有：

t = []
v = []

with open('data.txt', 'r') as f:
    for line in f:
        first, second = line.split()
        t.append(first)
        v.append(second)


print(t)
print(v)

現在我不確定下一步該去哪里。

理想情況下，我想計算相應時間的加速度，然后將其寫入具有 [time, acceleration] 的新文本文件，如下所示：

0       acceleration_value1
0.01    acceleration_value2
0.02    acceleration_value3
0.03    acceleration_value4
0.04    acceleration_value5

Answer 1

您的大部分代碼已經存在，但是它缺少從文件讀取的字符串轉換為float 。 除此之外，一個簡單的循環就可以完成這項工作。

t = []
v = []

with open('data.txt', 'r') as f:
    for line in f:
        first, second = line.split()
        t.append(float(first))    # note the 'float' conversion here
        v.append(float(second))

# Now, we will use an array to store the acceleration values
# The first element in this array will be zero, so:
a = [0]

# To calculate the acceleration, we will do delta(v)/delta(t),
# To calculate any delta, we will iterate each array, and pick
# the "current" and "previous" element. For this reason, our index
# will start at 1 skipping the first (otherwise we'll go to -1)

# these steps could be combined, but I feel it helps beginners to see
# the process

for i in range(1, len(v)):    # since v,t have same length, just pick either
    delta_v = v[i] - v[i-1]
    delta_t = t[i] - t[i-1]
    acc = delta_v / delta_t
    a.append(acc)

# Now we can print
# 'zip' combines the two arrays as columns of a matrix,
# so now "x" picks a value from "t", and "y" from "a" 
# as we iterate
for x, y in zip(t, a):
    print("%s  %s" % (x,y))

# or save to file:
with open("acceleration.txt", 'w') as f:
    for x, y in zip(t, a):
        f.write("%s  %s\n" % (x,y))

Answer 2

這應該給出每個時間戳的加速度列表

t = []
v = []

with open('data.txt', 'r') as f:
    for line in f:
        first, second = line.split()
        t.append(first)
        v.append(second)

acc = []
for i in range(len(t)):
  if i == 0:
    acc.append(0)
  else:
    acc.append((float(v[i]) - float(v[i-1])) / (float(t[i]) - float(t[i-1])))

print(acc)

Answer 3

我是 python 的新手，我有一個如下所示的文本文件：

0       10
0.01    10.0000001
0.02    10.00000113
0.03    10.00000468
0.04    10.0000128

它們分別是時間和速度的前幾個值。

我想將該文本文件讀入 Python 並使用這些值創建時間和速度變量，以便找到加速度。

到目前為止，我有：

t = []
v = []

with open('data.txt', 'r') as f:
    for line in f:
        first, second = line.split()
        t.append(first)
        v.append(second)


print(t)
print(v)

現在我不確定接下來要去哪里 go 。

理想情況下，我想計算相應時間的加速度，然后將其寫入具有 [時間，加速度] 的新文本文件，如下所示：

0       acceleration_value1
0.01    acceleration_value2
0.02    acceleration_value3
0.03    acceleration_value4
0.04    acceleration_value5