Python Learning Diary First article

One, Python number type

1, numeric types have integer type, floating point type and some of the more uncommon types, numeric types support mathematical operations

subtraction in [1]: + 45out[1]: 68In [2]: 1.7 + 2out[2]: 3.7In [3]: 2 * 10out[3]: 20In [4]: 10/2out[4]: 5In [5]: 23-45ou T[5]: -22in [6]: & 7out[6]: 4

2, the math module of Python math

Properties and methods of In [7]: import mathmath in [8]: math.math.acos        math.cos        math.factorial  math.ldexp       math.sinmath.acosh      math.cosh        math.floor      math.lgamma      math.sinhmath.asin       math.degrees     math.fmod       math.log         math.sqrtmath.asinh      math.e           math.frexp      math.log10       math.tanmath.atan       math.erf         math.fsum       math.log1p      math.tanhmath.atan2       math.erfc       math.gamma       math.modf       math.truncmath.atanh       Math.exp        math.hypot      math.pi          math.ceil        math.expm1      math.isinf      math.pow         math.copysign   math.fabs        math.isnan      math.radians   common function factorial: in [13]:  math.factorial (out[13]: ) 230843697339241380472092742683027581083278564571807941132288000000000000L Open Square In [14]: math.sqrT (out[14]: 7.3484692283495345) constant piin [15]: math.piout[15]: 3.141592653589793 

3. Random number Module

in [+]: import random1. Generate random number in [+]: Random.random () out[17]: 0.101435172235644362. Given random number generation range in []: Random.uniform ( 2, 3) out[18]: 2.8343477251262748In []: Random.uniform (100,3) out[19]: 84.883344129396963. Generates a random integer in [20] for a given range: Random.randint (3,4) out[20]: 34. Random selector in []: Random.choice ([1, ' a ', 3.4]) out[23]: 1In []: Random.choice ([1, ' a ', 3.4]) OUT[24]: 3.4In [+]: Random.choice ([1, ' a ', 3.4]) out[25]: ' A ' 5. Random reordering, in-situ modification in []: a = [1,2,3,4,5]in]: Random.shuffle ( a) in [aout[28]: [3, 1, 5, 2, 4]6. Random slices, without affecting the original sequence in [the]: Random.sample (a,2) out[34]: [1, 2]in []: aout[35]: [1, 2, 3, 4 , 5]

Two, Python string

A string is a sequence of strings of a single character that is immutable

1. String sequence manipulation

1. Define the string in [P]: a = ' Apache ' 2. String index (starting from 0, right starting from 1) in [PNS]: a[0]out[37]: ' A ' in []: a[1]out[38]: ' P ' in [All]: a[-1]out[39] : ' E ' 3. String slice in [max]: a[1:3]out[40]: ' pa ' in [P]: a[2:]out[41]: ' ache ' in [P]: a[:2]out[42]: ' ap ' in [Max]: a[:-1]out[43]: ' A Pach ' in [[]: a[-3:-1]out[44]: ' ch ' 4. String copy in [[]: B = a[:]in []: bout[46]: ' Apache ' 5. The character of the string is invariant in [h]: A + ' Web server ' out[47]: ' Apache Web server ' in [[]: aout[48]: ' Apache ' in [$]: A * 3out[49]: ' Apacheapacheapache ' in [[]: aout[50]: ' APA Che

2. String method

The usual string methods are as follows 1. Count occurrences of characters in a string in [Si]: a.count (' a ') out[54]: 2In [s]: A.count (' P ') out[55]: 12. Find the offset of the character in the string in [page]: A.find (' a ') OUT[57]: 0In []: A.find (' P ') out[58]: 13. Character substitution, do not modify metadata in [the]: A.replace (' A ', ' B ') out[59]: ' Bpbche ' in []: aout[60]: ' Apache ' 4. Uppercase conversion in [a]: A.upper () out[61]: ' Apache ' 5. Test string in [+]: A.isalpha () out[62]: True6. String split in [[]: b = "11:22:33:44 in [+]: B.split (': ') out[64]: [' 11 ', ' 22 ', ' 33 ', ' 44 ']7. Go to string trailing space in [the]: c = ' apache\n ' in [the]: c = C.rstrip () in []: CO UT[70]: ' Apache ' 8.python3.0 new feature: Replace in []: ' {0},2,{1},4 '. Format (' 1 ', ' 3 ') out[71]: ' 1,2,3,4 '

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Python Learning Diary First article